Arsenide Metal-semiconductor Field Effect Transistor Research Articles

Performances of novel Pd/Sn and Pd/Sn/Au ohmic metallizations to n-GaAs

Performance of novel Pd/Sn and Pd/Sn/Au Ohmic metallizations to n-GaAs have been investigated. Metallizations were deposited using a resistance heating evaporator and annealings were performed utilizing a conventional graphite strip annealer (cGSA). Metallization samples were characterized using scanning tunneling microscopy (STM), secondary ion mass spectrometry (SIMS) and current–voltage ( I– V) measurements. Contact resistivities, ρ c, of the metallizations were measured utilizing conventional transmission line model (cTLM) method. Novel Pd/Sn and Pd/Sn/Au Ohmic contacts exhibit better thermal stability compared to non-alloyed Pd/Ge metallization. In order to investigate the effectiveness of novel Pd/Sn and Pd/Sn/Au Ohmic metallizations in device applications, gallium arsenide metal-semiconductor field-effect transistors (GaAs MESFETs) have been fabricated. MESFETs fabricated with Pd/Sn/Au Ohmic contacts show a extrinsic transconductance, g me, of more than 133 mS/mm for a gate length, L G, of 2 μm.

Analysis of Surface States of Gallium Arsenide Metal Semiconductor Field-Effect Transistors using Drain Current Transients under Light Illumination

Characteristics of charge trapping at surface states of gallium arsenide metal semiconductor field-effect transistors (GaAs MESFETs) are analyzed using drain current transients under light illumination. Accurate trap density is obtained by classifying the transient into two components: one resulting from thermal emission and the other from light illumination. A slight decrease in delay time is observed under infrared light illumination having the photon energy lower than the band gap of GaAs. Pulse light illumination indicates an increase in charge trapping under the illumination during gate-off period.

Light Emission and Surface States Annealing on GaAs Metal Semiconductor Field-Effect Transistor

The annealing mechanism of surface states in the gallium arsenide metal semiconductor field-effect transistor (GaAs MESFET) is investigated by measuring the light-emission characteristics and excess gate currents generated by hot-carriers. Nonuniform light emission is observed when the Schottky junction is reverse biased, and the nonuniformity is increased with temperature. On the other hand, uniform and strong emission is observed under RF operation even when the device is biased with a deep pinch-off condition. The reverse and forward Schottky current caused by RF swing may not be a main emission mechanism under RF operation. Light emissions due to impact ionization and thermionic field emission are observed separately. The light intensity of the thermionic field emission has a weak temperature coefficient, while that of the impact ionization has a strong negative temperature coefficient. The decreasing rate of the surface states depends on the intensity and the distribution of the light emission during the operation.

New nonstationary velocity overshoot phenomenon in submicron gallium arsenide field-effect transistors

The gallium arsenide metal-semiconductor field-effect transistor (GaAs MESFET) with a gate length of 0.3 μm is numerically simulated in two dimensions using a semiclassical hot-electron transport model. A new type of nonstationary velocity overshoot is predicted in submicron devices. This new velocity overshoot phenomenon occurs in the drain region when the applied drain voltage is sufficiently large, so that a strong stationary high-field domain extended near the drain is developed in the region between the gate and the drain. The mechanism is found to be associated with a large mobility change by macroscopic intervalley transfer from the low-mobility higher energy satellite valleys to the high-mobility lower energy central valley in GaAs. In submicron GaAs MESFETs, this situation occurs as the electrons are rapidly cooled from the higher energy satellite valleys below the threshold energy during their transport across the depletion layer that developed near the drain electrode under large drain-bias conditions. Even though the mechanism involves initially heavy electrons under decreasing electric field conditions, it is found that a substantially high velocity overshoot is exhibited. The peak drift velocity attained reaches twice the maximum drift velocity obtainable under stationary conditions.

Focused ion implantation of gallium arsenide metal–semiconductor field effect transistors with laterally graded doping profiles

Implantation with finely focused beams of dopant ions scanned under computer control enables laterally graded doping profiles to be formed. A 150-nm-diam beam of silicon ions from a gold–silicon–beryllium liquid metal ion source has been used to fabricate GaAs metal–semiconductor field effect transistors (MESFET’s) incorporating a number of different laterally graded doping profiles. It is seen experimentally that, when compared with uniformly implanted devices, these MESFET’s display increased available output power and transductance.

A layer damage model for calculating thermal fatigue lifetime of power devices : Gao Guang-Bo, Chen An and Gui Xiang. 24 a. Proc. IEEE Reliab. Phys. Symp., 79 (1986)

Performance of novel Pd/Sn and Pd/Sn/Au Ohmic metallizations to n-GaAs have been investigated. Metallizations were deposited using a resistance heating evaporator and annealings were performed utilizing a conventional graphite strip annealer (cGSA). Metallization samples were characterized using scanning tunneling microscopy (STM), secondary ion mass spectrometry (SIMS) and current–voltage (I–V) measurements. Contact resistivities, ρc, of the metallizations were measured utilizing conventional transmission line model (cTLM) method. Novel Pd/Sn and Pd/Sn/Au Ohmic contacts exhibit better thermal stability compared to non-alloyed Pd/Ge metallization. In order to investigate the effectiveness of novel Pd/Sn and Pd/Sn/Au Ohmic metallizations in device applications, gallium arsenide metal-semiconductor field-effect transistors (GaAs MESFETs) have been fabricated. MESFETs fabricated with Pd/Sn/Au Ohmic contacts show a extrinsic transconductance, gme, of more than 133 mS/mm for a gate length, LG, of 2 μm.

The effect of long-term stress on filler-induced failure in high density RAMs : Kazutoshi Miyamoto, Osamu Nakagawa, Junichi Mitsuhashi and Heihachi Matsumoto. 24 a. Proc. IEEE Reliab. Phys. Symp., 51 (1986)

Performance of novel Pd/Sn and Pd/Sn/Au Ohmic metallizations to n-GaAs have been investigated. Metallizations were deposited using a resistance heating evaporator and annealings were performed utilizing a conventional graphite strip annealer (cGSA). Metallization samples were characterized using scanning tunneling microscopy (STM), secondary ion mass spectrometry (SIMS) and current–voltage (I–V) measurements. Contact resistivities, ρc, of the metallizations were measured utilizing conventional transmission line model (cTLM) method. Novel Pd/Sn and Pd/Sn/Au Ohmic contacts exhibit better thermal stability compared to non-alloyed Pd/Ge metallization. In order to investigate the effectiveness of novel Pd/Sn and Pd/Sn/Au Ohmic metallizations in device applications, gallium arsenide metal-semiconductor field-effect transistors (GaAs MESFETs) have been fabricated. MESFETs fabricated with Pd/Sn/Au Ohmic contacts show a extrinsic transconductance, gme, of more than 133 mS/mm for a gate length, LG, of 2 μm.