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In this work, we characterize the reaction of thin iron films deposited on Si(111) substrates upon annealing in the temperature range 200–600°C with Auger electron spectroscopy, electron energy loss spectroscopy, low energy electron diffraction and scanning electron microscopy. We particularly stress the conditions of formation and epitaxy of the disilicide FeSi 2 .

In this paper, we use Auger electron spectroscopy and electron energy‐loss spectroscopy in order to investigate the room‐temperature formation of the Ti/SiO2 interface and its reactivity upon annealing. We perform anneals in the temperature range 200–900 °C for which the phenomena involved are discussed with respect to the Si oxide and Ti film thicknesses.

The effect of gate-length variation on DC and RF performance of InAs/AlSb HEMTs, biased for low DC power consumption or high gain, is reported. Simultaneously fabricated devices, with gate lengths between 225 nm and 335 nm, have been compared. DC measurements revealed higher output conductance gds and slightly increased impact ionization with reduced gate length. When reducing the gate length from 335 nm to 225 nm, the DC power consumption was reduced by approximately 80% at an fT of 120 GHz. Furthermore, a 225 nm gate-length HEMT biased for high gain exhibited an extrinsic fT of 165 GHz and an extrinsic fmax of 115 GHz, at a DC power consumption of 100 mW/mm. When biased for low DC power consumption of 20 mW/mm the same HEMT exhibited an extrinsic fT and fmax of 120 GHz and 110 GHz, respectively.

We study the formation of the InP on GaAsSb interface grown by molecular beam epitaxy at 450 °C. Using angle resolved x-ray photoemission spectroscopy (XPS), we show that Sb strongly segregates whereas As does not, leading to a Sb-rich InP surface. Similarly, XPS spectra recorded on air-exposed samples reveal oxidized Sb but no oxidized As. We perform a quantitative analysis and determine a Sb segregation coefficient very near to 1. This result is in good agreement with previous reflectance anisotropy spectroscopy observations on the same interface.

Selective wet etching of Ga0.5In0.5Sb on Al0.55In0.45Sb and Al0.55In0.45Sb on Ga0.5In0.5Sb were demonstrated using tartaric acid and hydrochloric acid based solutions, respectively. Controllable etch rates in the range 400-1000 Aring/min resulting in smooth surfaces and selectivities of >10 suitable for use in HBT processing were achieved. By calculating the activation energies, we also determined the rate-limiting step in the etching.

Electrical characterization and modeling of 2 times 50 mum gatewidth InAs/AlSb HEMTs with 225 nm gate-length have been performed. The fabricated devices exhibited a transconductance gm of 650 mS/mm, an extrinsic cutoff frequency fT and an extrinsic maximum frequency of oscillation fmax of 120 and 90 GHz, respectively, already at a low VDS of 0.2 V. A minimum noise figure less than 1 dB between 2-18 GHz was achieved at a dc power consumption of only 10 mW/mm. This demonstrates the potential of InAs/AlSb HEMTs for low-power, low-noise applications. To account for the elevated gate-leakage current lG in the narrow-bandgap InAs/AlSb HEMT, the conventional field-effect transistor small-signal model has been extended. The relatively high IG was modeled by shunting both Cgs and Cgd with Rgs and .Rgd, respectively. As a result, the small-signal S-parameters were more accurately modeled, especially for frequencies below 10 GHz. Utilizing this modeling approach, excellent agreement was obtained between measured and modeled S-parameters, unilateral power gain U (Mason's gain) and stability factor K.

This work reports on the Te delta-doping of high electron mobility AlInSb/GaInSb heterostructures grown on InP(001). We show a significant increase of the electron sheet density when the delta-doping plane is incorporated in a thin AlSb layer introduced in the barrier. For the first time, AlInSb/GaInSb heterostructures with an electron mobility of 18,000 cm2/V.s and sheet density of 2.2times1012 cm-2 at room temperature are demonstrated.

In this paper, we present experimental results on AlSb/InAs HEMTs with deep and shallow mesa using wet and dry etching techniques respectively. Similar electrical results have been obtained using both techniques.

This work reports on the Te δ-doping of high electron mobility AlInSb/GaInSb heterostructures grown by molecular beam epitaxy on InP(001) substrates with a metamorphic approach. The combination of atomic force microscopy and van der Pauw measurements is used to investigate and explain the influence of the buffer layers on the electron mobility and sheet density in the heterostructure. Furthermore, a significant increase in the electron sheet density is reached when the δ-doping plane is incorporated in a thin AlSb layer introduced in the barrier. This improvement is explained by the lower dopant activation energy in the AlSb layer. AlInSb/GaInSb heterostructures with an electron mobility of 18 000 cm2/V s and sheet density of 2.2×1012 cm−2 at room temperature are demonstrated.

We report on the study of devices exploiting ballistic transport at room temperature by means of simulations and experimental results. Ballistic effects have been demonstrated at room temperature since a few years. This paper presents the work realised since 2001 on ballistic nanodevices at the Institut d'Electronique, Microelectronique et Nanotechnologie (IEMN). We will present the fabrication process and the characterisation of ballistic devices. We work on InGaAs-based devices optimised for ballistic transport, where the electron mean free path can reach around 130-160 nm at room temperature in channels with high indium content. We show that nanostructures around this size can be fabricated with the help of modem lithography techniques and are compatible with InP-HEMT technology. Devices under scope are Three-terminal Ballistic Junctions (TBJ) and their typical application is rectification. We have also characterised ballistic rectifiers up to 94 GHz. Measurements were realised on two TBJs integrated in parallel in a coplanar waveguide. We also show the frequency doubling characteristic of a single TBJ at 600 MHz.

In this paper, the formation of Er disilicide (ErSi2-x) with a Ti cap on low doping n -type Si(100) is investigated. After deposition in ultrahigh vacuum, the solid-state reaction between Er and Si is performed ex situ by rapid thermal annealing between 450 and 600 °C in a forming gas ambience with a 10 nm thick Ti capping layer to protect Er from oxidation. X-ray diffraction analyses have confirmed the formation of ErSi2-x for all annealing temperatures. The formed films are found to be free of pinholes or pits and present a sharp and smooth interface with the Si bulk substrate. The extracted Schottky barrier height (SBH) corresponds to the state-of-the-art value of 0.28 eV if the annealing temperature is lower than or equal to 500 °C. This result demonstrates the possibility to form low SBH ErSi2-x /n-Si contacts with a protective Ti cap. However, when the annealing temperature is set to a higher value, the SBH concomitantly rises. Based on our experiments, this SBH increase can be mainly related to an enhanced diffusion of oxygen through the stack during the annealing, which degrades the quality of the ErSi2-x film.

We present a detailed study of interface formation in the titanium-silicon (Ti-Si) system under different temperature conditions. We make use of electronic-structure calculations in order to interpret the silicon Si ${L}_{2}$,3VV Auger line shape and the electron-energy-loss spectra. These techniques, together with low-energy electron diffraction and electron-microscopy observations and film-resistance data, allow us to discuss accurately the interface reactivity of the Ti-Si system with respect to temperature.

Combining Scanning Gate Microscopy (SGM) experiments and simulations, we demonstrate low temperature imaging of electron probability density $|\Psi|^{2}(x,y)$ in embedded mesoscopic quantum rings (QRs). The tip-induced conductance modulations share the same temperature dependence as the Aharonov-Bohm effect, indicating that they originate from electron wavefunction interferences. Simulations of both $|\Psi|^{2}(x,y)$ and SGM conductance maps reproduce the main experimental observations and link fringes in SGM images to $|\Psi|^{2}(x,y)$., Comment: new title

InAs/AlSb HEMTs with gate lengths in the range 225-335 nm processed on the same wafer have been investigated with respect to DC and RF performance. While the magnitude of the transconductance gm was similar for all gate lengths, the shortest gate length HEMT exhibited the highest extrinsic maximum frequency of oscillation fmax and extrinsic current gain cut-off frequency fT of 115 GHz and 165 GHz, respectively.

Dry etching of AlSb and Al0.80Ga0.20Sb has been performed by inductively coupled plasma/reactive ion etching based on a (Cl2:Ar) gas mixture without addition of BCI3. The dry etch process has been used to fabricate AlSb/InAs high electron mobility transistors isolated by a shallow mesa. Good DC/RF results, with extrinsic fT/fmax= 135/105 GHz, have been measured for a 2times50 mum HEMT with a gate length of 295 nm.

A detailed study of the formation of iridium silicide obtained by ultrahigh vacuum annealing and atmospheric rapid thermal processing is proposed using x-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and electrical characterizations. Using XPS analysis, the stoichiometry of each silicide phase (IrSi, IrSi1.6) is identified. A model based on the variation of the measured intensity of the Ir 4f spectra is used to obtain the kinetic coefficients of reaction of Ir silicidation (EA=2.48eV, D0=9cm2∕s). TEM cross sections indicate that the roughness of the silicide∕silicon interface increases with temperature. Lastly, electrical characteristics are used to identify the optimum annealing temperature to obtain an iridium silicide contact with the lowest Schottky barrier height to holes.

The paper reports on the covalent attachment of semicarbazide functional groups onto hydrogen-terminated silicon-rich silicon nitride (SixN4; 4

Gold electrodes have been deposited by transfer printing (TP) on a thiol-functionalized self-assembled monolayer (SAM) on silicon substrate. A sequential chemical route is reported to incorporate thiol groups (−SH) on a preformed long alkyl chain SAM on silicon. The structural characterizations of the functionalized surfaces are described and confirm success of each chemical step (overall yield of 20%). The electrical measurements of the silicon−molecules−gold TP junctions are compared with junctions made by a classical vacuum evaporation of gold. The temperature-dependent electrical measurements show that the silicon/alkyl/Au TP junctions exhibit a purely temperature-independent tunnel behavior, while a slight temperature-dependent behavior is observed at a low bias (|V| < 0.5 V) for the junctions with evaporated Au electrodes. Admittance spectroscopy measurements confirm the better dielectric behavior of TP junctions.

In this paper, we present a study on three-terminal ballistic junction and their applications to rectifiers and MUX/DEMUX. Rectifying effect is observed up to 94 GHz at room temperature. Although THz frequency performance has been demonstrated by Monte Carlo simulation, the high impedance of the nano-device combined with the parasitic capacitances is a limiting factor. (c) 2006 Published by Elsevier B.V.

AlSb/InAs heterostructures show promising characteristics for the realisation of very high electron mobility devices. This report focuses on the metamorphic growth of these structures on InP substrate with GaSb and AlSb buffers. We observe poorer low-temperature electron mobility and room temperature (RT) densities using an AlSb buffer. The photoluminescence (PL) of a GaSb quantum well (QW) grown on the two kinds of buffers suggests that this difference does not result from a larger density of dislocations with an AlSb buffer. The hypothesis of a strain relaxation in the InAs channel on AlSb is also denied since a heterostructure with a thinner InAs QW does not show a higher electron mobility. This leads us to discuss the influence of the roughness of the buffer layer on the temperature mobility and the density of the two-dimensional electron gas.

this works reports on speed and high performance benchmarking of low band gap III-V based-HEMTs versus advanced n-MOSFET in low drain voltage regime (few kT/q). In this low bias condition, figure of merits such as, fT are higher and intrinsic gate delay and energy are almost one order of magnitude lower in the case of III-V based-devices (two orders of magnitude for the delay-energy product).

Fabrication and characterization of 225 nm gate-length InAs/AlSb HEMTs with excellent RF performance are reported. We show the importance of an insulating layer between the gate and the semiconductor to improve gm, fT and fmax, and most important from a noise perspective, the gate-leakage current IG. By using an insulated-gate, IG was reduced by two orders of magnitude. The insulated-gate HEMTs exhibited extrinsic fT and fmax of 155 GHz and 115 GHz, respectively, at VDS=0.5 V.

Silicon δ-doped layers in GaAs have been studied using scanning tunneling microscopy and scanning tunneling spectroscopy on cleaved (110) surfaces. The samples were grown using molecular beam epitaxy with two growth temperatures: 480 and 580 °C. The concentration of the δ-doped layer was 0.03 monolayer. We show that, as in the case of bulk doping, the silicon has an amphoteric character: both SiGa and SiAs are observed at 480 °C and donors are formed before acceptors. At 580 °C, the spatial repartition of silicon evidences the segregation of silicon.

InAlAs–InP type II heterostructures grown by gas-source molecular beam epitaxy have been studied by photoluminescence. The interface recombination energy is found around 1.27–1.28 eV in the low injection limit and shifts towards higher energy when increasing the incident power. Similar results are obtained for direct (InAlAs grown on InP) and inverse (InP on InAlAs) structures.

In this work we report on the state-of-the-art combination at V-band between simultaneously power density (370 mW/mm), power-added efficiency (28.3%), and power gain (5.2 dB) of InP pseudomorphic HEMTs biased at a low drain voltage of 2 V. The performance of these double delta-doped pseudomorphic AlInAs-GaInAs HEMTs on InP with an original strain compensated channel was measured at 60 GHz. This demonstrates a good potentiality for low-voltage applications in order to reduce the power supply of systems.

Traditionally, the understanding of quantum transport, coherent and ballistic1, relies on the measurement of macroscopic properties such as the conductance. While powerful when coupled to statistical theories, this approach cannot provide a detailed image of "how electrons behave down there". Ideally, understanding transport at the nanoscale would require tracking each electron inside the nano-device. Significant progress towards this goal was obtained by combining Scanning Probe Microscopy (SPM) with transport measurements2-7. Some studies even showed signatures of quantum transport in the surrounding of nanostructures4-6. Here, SPM is used to probe electron propagation inside an open quantum ring exhibiting the archetype of electron wave interference phenomena: the Aharonov-Bohm effect8. Conductance maps recorded while scanning the biased tip of a cryogenic atomic force microscope above the quantum ring show that the propagation of electrons, both coherent and ballistic, can be investigated in situ, and even be controlled by tuning the tip potential., Comment: 11 text pages + 3 figures

We present an experimental comparison of magnetoconductance fluctuations measured in the ballistic, quasiballistic, and diffusive scattering regimes of semiconductor devices. In contradiction to expectations, we show that the spectral content of the magnetoconductance fluctuations exhibits an identical fractal behavior for these scattering regimes and that this behavior is remarkably insensitive to device boundary properties. We propose a unified model of fractal conductance fluctuations in the ballistic, quasiballistic, and diffusive transport regimes, in which the generic fractal behavior is generated by a subtle interplay between boundary and material-induced chaotic scattering events.

This work is a quantitative study of the conditions required for a long-term passivation of the interface silicon-alkyl monolayers prepared by thermal hydrosilyation of neat 1-alkenes on well-defined H-Si(111) surfaces. We present electrochemical capacitance measurements (C-U) in combination with ex situ atomic force microscopy (AFM) observations and X-ray photoelectron spectroscopy (XPS) measurements. Capacitance measurements as a function of the reaction time and XPS data reveal close correlations between the chemical composition at the interface and its electronic properties. A very low density of states is found if suboxide formation is carefully prevented. The monitoring of C-U plots and AFM imaging upon exposure of the sample in diverse conditions indicate that the initial electronic properties and structure of the interface are long-lasting only when the monolayer surface coverage is theta0.42. A model demonstrates that this threshold value corresponds to a monolayer with intermolecular channels narrower than approximately 2.82 A, which is equal to the diameter of a water molecule. Water exclusion from the monolayer promotes long-term passivation of the silicon surface against oxidation in air and water as well as perfect corrosion inhibition in 20% NH(4)F. We provide two criteria to assess when a sample is optimized: The first one is an effective dielectric constant2.5, and the second one is a very characteristic energy diagram at open circuit potential.

We present our experimental investigations on the low-temperature (T) saturation of the electron phase coherence time TO in open ballistic quantum dots fabricated from InGaAs/InAlAs heterostructures. At high temperature, we observe that tau(phi) = aT(-p), with 2/3 < p < 2. The constant a is strongly influenced by the population of the second electronic subband in the quantum well. Below a temperature T-onset, in the range 0.5 K < T-onset < 5 K, tau(phi) saturates in all our samples. The condition for the occurrence of saturation is found to be T-phi, (sat) = tau(d), where T-phi,T- sat is the saturated coherence time and tau(d) is the dwell time. We discuss possible interpretations for this observation. (c) 2006 Elsevier B.V. All rights reserved.

We report on the design, fabrication and characterization of 100nm T-gates In0.52Al0.48As/In0.53Ga0.47 As double-gate HEMTs (DG-HEMT) on InP substrate. In comparison with single gate conventional HEMT, maximum oscillation frequency (fmax) was increased by 30% when the DG-HEMT operate in simple gate command (DG-HEMT-SC) due to the reduction of short channel effects. On the other hand, in double-gate command operation mode (DG-HEMT-DC), control of the threshold voltage of DG-HEMT was achieved while keeping constant DC and RF performances. In this operation mode, these three-port devices were considered as being very effective for millimeter-wave mixing applications and were promising devices for the fabrication of velocity modulation transistor (VMT) (Sakaki, 1982)

We describe the photochemical oxidation of polycrystalline boron-doped diamond films by UV irradiation in air at room temperature. The reaction generates surface hydroxyl groups that have been coupled with perfluorodecyl trichlorosilane to yield an organic layer covalently attached to the diamond surface. The resulting surfaces were characterized using X-ray photoelectron spectroscopy, contact angle and cyclic voltammetry. Keywords: Boron-doped polycrystalline diamond, Photochemical oxidation, Electrochemical properties, Surface chemical reactivity

We investigate GalnP/GaAs high electron mobility transistor structures grown in a production MBE system, with different interface commutation procedures. They have been designed to be very sensitive to the interface quality. They have been characterized by Hall measurements and photoluminescence. GaP-type and GalnAs-type interfaces can be distinguished. Best mobility results occur for few second or even no growth interruption, demonstrating the very low As memory effect of this large system.

We present measurements of the electron phase coherence time tau(varphi) on a wide range of open ballistic quantum dots (QDs) made from InGaAs heterostructures. The observed saturation of tau(varphi) below temperatures 0.5 K

We present the optimization of the metamorphic growth of InAs/InAlAs heterostructures on InP(001). We obtain the best electron mobility, 21500 cm/sup 2//V.s at 300K and 179000 cm/sup 2//V.s at 77K, with a composite InAs/InGaAs channel.

THz radiations present a great interest for applications in different fields ranging from telecommunications to sensors for biology and medicine. This paper reviews two new field effect devices especially suited for THz applications: double-gate HEMTs (DG-HEMT) and plasma wave transistors

The interactions of PTCDA molecules with the Si(1 0 0) surface have been investigated by means of X-ray photoelectron spectroscopy (XPS) and scanning tunnelling microscopy (STM). Among the large distribution of the adsorbates observed by STM for submonolayer coverages, around 20% show a distinct feature, which is interpreted as the product of the covalently linkage between PTCDA and Si atoms. The formation of this product through the anhydride groups is further supported by the XPS measurements. The occurrence of different adsorption states results eventually in the formation of a disordered initial layer, which nevertheless acts as a passivation layer and leads to the formation of islands for coverage above 1 ML. These islands have a common layer structure, similar to the molecular arrangement found in the (1 0 2) plane of PTCDA bulk phase.

We have investigated InP HEMT structures with large band gap channels for power amplification at 94 GHz. We show that structures containing InP an InAsP channels are very promising for power amplification at 94 GHz.

InAs has been studied as the active material of metamorphic InAlAs∕InAs modulation-doped heterostructures grown on InP. We show that the main limitation of these structures is the plastic relaxation of the 10–15nm thick InAs channel compressively strained to the underlying InAlAs buffer. The best results are obtained with a composite channel made of 7nm InAs inserted in an InGaAs layer. In this case, the electron mobility reaches 21 500 and 179000cm2∕Vs at 300 and 77K, respectively, for a sheet carrier density of 9×1011cm−2. These values are among the highest ones ever reported for such metamorphic structures.

We have developed new solutions for InP high-electron mobility transistor (HEMT) scaling for power applications at W band. We have shown that the use of a small barrier thickness in order to respect the aspect ratio for a 70-nm gate length results in a significant kink effect and high gate source capacitances. We have also shown through a theoretical study that a structure containing an InP layer between the cap layer and the barrier would support both the frequency performances and the breakdown voltage. Thus, we propose an HEMT structure containing a thick InP/AlInAs composite barrier and where the gate is buried into the barrier. This enables us to respect the aspect ratio and simultaneously to obtain an important drain current density without observing any kink effect. Moreover, we have applied this process to structures containing innovative large band-gap InP and InAsP channels. We have achieved the best frequency performances ever reached for an InP channel HEMT structure. Power measurements at 94 GHz were performed on these devices. The InAsP channel HEMT demonstrated a maximum output power of 260 mW/mm at 3 V of drain voltage with 5.9-dB power gain and a power-added efficiency of 11%. These results are favorably comparable to the state-of-the-art of InP-based HEMT at this frequency.

Despite the importance of the isocyanate group in chemistry, very few examples of isocyanate-modified silicas have been reported, and all of the strategies described so far led to partial or total hydrolysis or condensation of the isocyanate group. By synthesizing trichlorosilane isocyanate as the coupling reagent, we show that oxidized silicon wafers are successfully modified with the isocyanate group. Our method is achieved in mild conditions, at low temperature, without side-reactions and allows the formation of a self-assembled monolayer (SAM) of isocyanates. The isocyanate group then offers a flexible way to further functionalize silica substrates with different nucleophiles, due to its high and specific reactivity.

Methyl radical beam sources for ultra high vacuum applications have been characterised using ionisation threshold mass spectrometry. Methane, ethane and acetone have been dissociated in a resistively heated carbon gas cracker cell. The effect of pressure on the methyl radicals formation has been studied independently of the precursor gas flow by changing the cell conductance. Methyl radical fluxes heavily depend on the pressure and the nature of precursor, ranging from 1 x 10 15 cm -2 s -1 for a methane flow of 1 sccm up to 2 x 10 16 cm -2 s -1 when acetone is used.

International audience; We have developed technology based on GaInAs/AlInAs for building ballistic devices working at room temperature. We first present here processes for passive and active devices (T-branch junctions (TBJs), Y-branch junctions (YBJs) and TBJs with Schottky gates. Then, we present DC characterization of TBJs to prove the ballistic behaviour and new results for YBJs.

100nm T-gates InP double-gate HEMTs (DG-HEMT) have been fabricated by use of transferred substrate technique. Theses devices are compared with standard single 100nm T-gate HEMT. The maximum extrinsic transconductance gm of DG-HEMT is two times higher than the HEMT one, and the extrinsic output conductance gd is significantly reduced with DG-HEMT. The combined high gm and low gd induced an extremely high intrinsic unloaded voltage gain gm/gd of 100. So, theses results allowed an improvement of the maximum oscillation frequency (f/sub max/) of 30% compared with standard single 100nm T-gate HEMT. These results are attributed to reduction of short channel effects, related to higher charge control efficiency and suppression of buffer effect.

Segregation of column III atoms during molecular beam epitaxy of III‐III’‐V semiconductor compounds causes nonabrupt interfaces and a surface composition different from the bulk one. To derive concentration profiles, a thermodynamical equilibrium model has been used for a long time. This model applies well to describe segregation processes at high growth temperatures, but fails in predicting concentration profile variations with substrate temperature. We have thus developed a kinetic model which correctly takes into account the evolution with the growth temperature. We apply this model to the case of indium segregation in the GaxIn1−xAs/GaAs system. The calculated indium concentration profiles are compared to those obtained with the thermodynamical equilibrium model. A kinetic limitation of segregation is shown to appear at low substrate temperatures and sufficiently high growth rates. This limitation is predicted to arise below 400 °C for a growth rate of 1 monolayer/s for In segregation in the GaxIn1−xA...

By using a semi-classical 2D Monte Carlo simulation, simple ballistic devices based on AlInAs/InGaAs channels are analyzed. Our simulations qualitatively reproduce the main features of the experimental results in T-branch and Y-branch junctions as well as in a ballistic rectifier appearing as a result of electron ballistic transport. We show that a quantum description of electron transport is not essential for the physical explanation of these results, since phase coherence plays no significant role. On the contrary, its origin can be purely classical: the presence of classical electron transport and space charge inside the structures.

A detailed analysis of the formation of Pt 2 Si and PtSi silicides is proposed, based on x-ray photoelectron spectroscopy ~XPS!, transmission electron microscopy ~TEM!, and electrical characterizations. Published kinetics of the Pt 2 Si and PtSi transformations under ultrahigh vacuum condition are consolidated on the basis of XPS measurements performed during an in situ annealing at a constant heating rate. At room temperature, an incomplete PtxSi reaction is clearly identified by XPS depth profiling. Using rapid thermal annealing at 300, 400, and 500 °C, the sequential Pt‐Pt2Si‐PtSi reaction chain is found to be completed within 2 min. Outdiffusion of silicon to the top surface is shown to be responsible for the formation of a thin SiO2 capping layer at 500 °C. Pileup of oxygen occurring at the Pt2Si/Pt reaction front is clearly identified as an inhibiting factor of the silicidation mechanism. Another incomplete reaction scheme limited to the unique formation of Pt2Si is exemplified in the case of ultra thin silicon-on-insulator films. Finally, current drive measurements on PtSi Schottky contacts have allowed us to identify 300 °C as the optimum annealing temperature while TEM cross sections demonstrate the formation of a smooth and continuous PtSi/Si interface at 300 °C. © 2003 American Institute of Physics. @DOI: 10.1063/1.1605817#

The authors present a novel process for fabrication of deep submicron isolation patterns in InAs/Al80Ga20Sb heterostructures. The process is demonstrated by processing InAs/Al80Ga20Sb self-switching diodes (SSDs). SSDs require high-resolution isolation patterns, which presents a major fabrication challenge because of the oxidation sensitivity of Al(Ga)Sb alloys. The presented fabrication process completely avoided exposure of Al(Ga)Sb to air and resulted in an isolation pattern with a feature size down to 35 nm. The process was based on a dry etch of isolating trenches, in situ removal of the resist etch mask followed by in situ encapsulation of etched surfaces by silicon nitride. The applicability of the InAs/Al80Ga20Sb SSD process was demonstrated with on-wafer RF measurements of zero-bias detection up to 315 GHz. Below 50 GHz, the detector's noise-equivalent power was estimated to less than 100 pW/Hz½.

The growth of strained Ga/sub 1-x/In/sub x/P alloys on GaAs substrate with the indium composition varying from 0 (GaP) to 1 (InP) was studied by means of reflection high energy electron diffraction (RHEED). Compressive layers (x>0.48) exhibit an InGaAs-like behaviour. Below 2% misfit strain (x/spl les/0.75) plastic relaxation occurs before the 2D-3D growth mode transition for which the lattice parameter relaxation is observed directly on the RHEED pattern. However, growth temperature has not a strong influence on the relaxation behaviour as in the InGaAs/InP system. On the other hand, if layers under tensile strain have a normal behaviour at low temperature, the critical thickness is found to be independent of the composition for x