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Recent measurements of heavy-ion-induced charge-collection transients are presented. These measurements are possible for the first time because of recent developments in highbandwidth, single-shot measurement technology, and exhibit several significant advantages over conventional (charge-sensitive preamplifier) charge-collection measurements. Heavy-ion induced transient measurements are presented for InGaAs/InAIAs HEMTs, AISb/InAs HEMTs, GaAs HFETs and for SOI NMOS devices, and the significant advantages of this approach are described. Index Terms--AISb/InAs HEMT, charge collection, InGaAs HEMT, laser SEE, single event effects, SOI, transient measurement.

A study of the low-noise characteristics of AlSb/InAs and related high-electron mobility transistors (HEMTs) in the 6.1-A-lattice-constant material system is presented. The effect of gate bias is reported and comparisons are made to noise performance of several InAs-based HEMTs with different layer structure and channel composition.

The single-event effects response of three different III-V field-effect transistor technologies (GaAs MESFET, InAIAs/InGaAs HEMT, and AISb/InAs HEMT) is measured for MeV and GeV heavy-ion irradiation. These measurements reveal significant charge enhancement and very slow, microsecond-timescale relaxation times for the GaAs and InAIAs/InGaAs devices, with a much faster recovery from the ionizing event observed for the AISb/InAs HEMTs. Index Terms--AISb, charge collection, GaAs, HEMT, InAIAs, InAs, InGaAs, InP, MESFET, single-event transient, single-event upset.

Time-resolved charge-collection measurements are performed on InAIAs/InGaAs HEMTs with pulsed laser excitation as a function of device bias conditions and the incident laser pulse energy. The results provide clear evidence for the presence of charge-enhancement processes that, in many ways, are analogous to those observed previously for GaAs FET technology. Index Terms--HEMT, InAIAs, InAIAs/InGaAs, InGaAs, InP HEMT, SEU, single-event effects, single-event upset.

The Al(sub x)Ga(sub 1-x)Sb(sub y)As(sub 1-y)/InAs material system, where the lattice constant is near 6.1 angstroms, was used to study high efficiency mobility transistors with only InAs as the channel material. Their better InAs properties and the larger conduction band offset at the AlSb/InAs heterojunction demonstrate their potential for low-voltage, high-speed applications. The devices exhibit a transconductance of 600 mS/mm and an f(sub T) of 120 GHz at V(sub DS) = 0.6 V. With technological improvements, noise figures of 0.3 dB at 4 GHz and 0.6 dB at 10 GHz can be achieved.

The influence of trapping mechanisms on the transconductance of single- and double-recessed InAlAs/InGaAs/InP high electron mobility transistors is studied. There are two mechanisms with different activation energies. One mechanism, which induces negative dispersion, has an activation energy of 0.17 eV and can be found only in the double-recessed structure. The other mechanism, which induces positive dispersion and common to both structures, has a dominant transition with an activation energy of 0.51 eV at low fields.

An examination of the kink effect in InAlAs/InGaAs/InP HEMTs in the frequency and time domains reveals its association with various deep levels in the InAlAs. The sinusoidal excitation below the kink voltage produces two prominent output-resistance-frequency transitions at trap activation energies of 0.18 and 0.56 eV caused by the traps in InAlAs or its interfaces. Excitation above the kink voltage yields a single broad transition at 0.24 eV. Excitation by incremental voltage pulses produces the actual kink signature.

The article studies the spatial localization of 1/f noise source in AlSb/InAs high-electron-mobility transistors using Langevin random method. Findings reveal that density of noise sources in IAs channel is much larger near the top interface than at the bottom interface.

Time-resolved charge-collection measurements are performed on AlSb/InAs HEMTs with pulsed laser excitation as a function of device bias conditions and the incident laser pulse energy. The results provide clear evidence for the presence of charge-enhancement processes that, in many ways, are analogous to those observed previously for GaAs FET technology.