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An AlGaN/GaN high electron mobility transistor with a Si3N4 passivation layer is prepared that is deposited in situ in metal-organic chemical-vapor deposition reactor in the same growth sequence, as the rest of the layer stack. The SiN4 is shown to be of high quality and stoichiometric in composition.

It has been shown that the statistical techniques conventionally used for thin SiO2 layers can be used to investigate the degradation and breakdown of magnetic tunnel junctions. It was found that there is a conductance change of the tunnel junction when the junction is stressed with a constant current or voltage.

A study was conducted to analyze a magnetoresistive random access memory for an array of magnetic memory cells. Each memory cell supported a giant magnetoresistive spin-valve structure in series with a gallium arsenide diode. The diode resistance decreases as a function of the applied current. Experimental results indicated on-chip switching using a coincident current scheme, reproducible on-chip readout, and process compatibility.

Dielectric properties of annealed and as-grown ferroelectric Ba0.5Sr0.5TiO3 (BST) grown by pulsed laser deposition on sputtered BST seed layers on strontium titanate (STO) substrates were investigated at microwave frequencies in the realm of tunability of its dielectric constant as well as phase shifters based on this material. The as-grown layers were nearly fully relaxed with measured lattice parameters nearly identical to those of bulk BST. The tuning of the relative dielectric constant (∼1750 at zero bias at 10 GHz) of the annealed BST was found to be as high as 59% and 56% at 10 and 19 GHz, respectively. The analysis of the loss in the BST results in a measured tan δ of 0.02 for the annealed as well as the unannealed films at a frequency of 18 GHz. Phase shifters also exhibited high tuning with differential phase shift figures of merit of 35 and 55°/dB at a field of 60 kV/cm at 10 and 19 GHz, respectively. Serendipitously, most of the tuning occurs at low fields, and thus we propose a new figure of merit, taking into account the amplitude of applied electric field in order to achieve the phase shift. In this new realm we achieved the values of this overall figure of merit of 1.2 and 1.8° cm/dB kV at 10 and 19 GHz, respectively, using an applied electric field of only 10 kV/cm. [ABSTRACT FROM AUTHOR]

We report on the evolution of the atomic-scale strain tensor of ductile Zr64.13Cu15.75Ni10.12Al10 bulk metallic glass under tensile loading by using x-ray synchrotron radiation. The same kind of samples was previously investigated under compressive loading and revealed yielding at 1690 MPa together with large deformability of up to 160% strain. In tension the samples fracture at a lower stress, 1500 MPa, with no sign of yielding or plastic deformation. With no macroplasticity observed under tension, large differences in the elastic constants obtained from the strain tensor and from ultrasonic sound velocity measurements are revealed. This paper presents in detail the measuring procedure as well as the calculation of the tensile tensor and pair distribution functions of Zr64.13Cu15.75Ni10.12Al10 at different stages of deformation. The results are discussed in comparison with other reported data obtained from x-ray diffraction measurements using synchrotron radiation. [ABSTRACT FROM AUTHOR]

We have made AlGaN/GaN high electron mobility transistors with a Si3N4 passivation layer that was deposited in situ in our metal-organic chemical-vapor deposition reactor in the same growth sequence as the rest of the layer stack. The Si3N4 is shown to be of high quality and stoichiometric in composition. It reduces the relaxation, cracking, and surface roughness of the AlGaN layer. It also neutralizes the charges at the top AlGaN interface, which leads to a higher two-dimensional electron-gas density. Moreover, it protects the surface during processing and improves the Ohmic source and drain contacts. This leads to devices with greatly improved characteristics. [ABSTRACT FROM AUTHOR]

Dielectric properties of annealed and as-grown ferroelectric [Ba.sub.0.5][Sr.sub.0.5]Ti[O.sub.3] (BST) grown by pulsed laser deposition on sputtered BST seed layers on strontium titanate (STO) substrates are examined at microwave frequencies in the region of tenability of its dielectric constants as well as phase shifters. Studies have shown that most of the tuning has occurred at low fields and hence a new figure of merit is proposed by considering the amplitude of applied electric field in order to achieve the phase shift.

Contactless electroreflectance (CER) is used for studying the AlGaN potential-barrier height in AlGaN/GaN heterostructures without and with a SiN passivation layer. The studies have shown that the SiN-related shift in the Fermi level position at the AlGaN surface should be smaller than 0.7 eV.

The evolution of the atomic-scale strain tensor of ductile [Zr.sub.64.13][Cu.sub.15.75][Ni.sub.10.12][Al.sub.10] bulk metallic glass under tensile loading is studied by using x-ray synchrotron radiation. The type and concentration of the constituent elements in the [Zr.sub.64.13][Cu.sub.15.75][Ni.sub.10.12][Al.sub.10] alloy have shown that Zr-Zr, Zr-Cu and Zr-Ni are the dominant atomic pairs, which have constituted the first coordination shell of the pair distribution functions (PDFs).

The reliability of magnetic tunnel junctions (MTJs) with a 1.6 nm Al2O3 tunnel barrier formed by ultraviolet light assisted oxidation is examined. The breakdown mechanism in MTJs is highlighted.

Detailed, spatially, temporally, and vectorially resolved, ultrafast scanning Kerr microscopy data of precessional switching in a macrospin in a crossing-wire geometry is discussed. The spatial variation must therefore be a demagnetizing maneuver by the element seeking to lower its energy and, as such, may also be affected by the magnetic background material around the element.

Presents information on a study which evaluated the diffusion of ion-implanted copper (Cu) in Kapton films by Rutherford backscattering. Interactions between the metal interconnects and polymide insulators in very large scale integration processes and printed circuit board applications; Ion implantation of Cu into four Kapton types; Diffusion and self-gettering of Cu; Thermal stability of polymide films.

The development of magnetic random access memory requires very reliable magnetic tunnel junctions (MTJs). A constant voltage stress test is performed to investigate the reliability of the magnetic tunnel junctions (MTJs).

A method for controlled transport and manipulation of magnetic beads over the chip's surface towards a spin-valve sensor and subsequently detected the particles through the change in the magnetoresistance (MR) signal of the sensor is investigated. It shows that the prototype sensor system gives us a tool by which to understand the magnetic behavior of the particles while moving across the sensor.

An experimental examination of the properties of the Si(100)-SiO[sub 2] interface measured following rapid thermal processing (RTP) is presented. The interface properties have been examined using high frequency and quasi-static capacitance-voltage (CV) analysis of metal-oxide-silicon (MOS) capacitor structures immediately following either rapid thermal oxidation (RTO) or rapid thermal annealing (RTA). The experimental results reveal a characteristic peak in the CV response measured following dry RTO and RTA (T>800 °C), as the Fermi level at the Si(100)-SiO[sub 2] interface approaches the conduction band edge. Analysis of the QSCV responses reveals a high interface state density across the energy gap following dry RTO and RTA processing, with a characteristic peak density in the range 5.5x10[sup 12] to 1.7x10[sup 13] cm[sup -2] eV[sup -1] located at approximately 0.85-0.88 eV above the valence band edge. When the background density of states for a hydrogen-passivated interface is subtracted, another peak of lower density (3x10[sup 12] to 7x10[sup 12] cm[sup -2] eV[sup -1]) is observed at approximately 0.25-0.33 eV above the valence band edge. The experimental results point to a common interface state defect present after processes involving rapid cooling (10[sup 1]-10[sup 2] °C/s) from a temperature of 800 °C or above, in a hydrogen free ambient. This work demonstrates that the interface states measured following RTP (T>800 °C) are the net contribution of the P[sub b0]/P[sub b1] silicon dangling bond defects for the oxidized Si(100) orientation. An important conclusion arising from this work is that the primary effect of an RTA in nitrogen (600-1050 °C) is to cause hydrogen desorption from pre-existing P[sub b0]/P[sub b1] silicon dangling bond defects. The implications of this work to the study of the Si-SiO[sub 2] interface, and the technological implications for silicon based MOS processes, are briefly discussed. The significance of th... [ABSTRACT FROM AUTHOR]

Dielectric properties of annealed and as-grown ferroelectric Ba0.5Sr0.5TiO3 (BST) grown by pulsed laser deposition on sputtered BST seed layers on strontium titanate (STO) substrates were investigated at microwave frequencies in the realm of tunability of its dielectric constant as well as phase shifters based on this material. The as-grown layers were nearly fully relaxed with measured lattice parameters nearly identical to those of bulk BST. The tuning of the relative dielectric constant (∼1750 at zero bias at 10 GHz) of the annealed BST was found to be as high as 59% and 56% at 10 and 19 GHz, respectively. The analysis of the loss in the BST results in a measured tan δ of 0.02 for the annealed as well as the unannealed films at a frequency of 18 GHz. Phase shifters also exhibited high tuning with differential phase shift figures of merit of 35 and 55°/dB at a field of 60 kV/cm at 10 and 19 GHz, respectively. Serendipitously, most of the tuning occurs at low fields, and thus we propose a new figure of merit, taking into account the amplitude of applied electric field in order to achieve the phase shift. In this new realm we achieved the values of this overall figure of merit of 1.2 and 1.8° cm/dB kV at 10 and 19 GHz, respectively, using an applied electric field of only 10 kV/cm. [ABSTRACT FROM AUTHOR]