Sulfur passivation of GaAs metal-semiconductor field-effect transistor

Abstract

A passivation technique consisting of a (NH4)2S dip followed by GaS deposition has been applied to a GaAs microwave-power metal–semiconductor field-effect transistor (MESFET). The breakdown characteristic of the MESFET is greatly improved upon the (NH4)2S treatment, and a stable passivation effect can be achieved by GaS film deposition. It is found that the FET current–voltage characteristics are closely related to variations in the pinning position of the GaAs surface Fermi level. With the surface passivated, a depletion layer can be properly formed and protected, which is of benefit to the control of the device parameters.

Low interface state density and low leakage current of atomic‐layer deposited TiO2/Al2O3/sulfur‐treated GaAs

“…The (NH 4 ) 2 S solution is a moderate etchant to reduce surface oxides on GaAs. Meanwhile, GaAs surface will be effectively passivated with sulfur atoms to prevent it from oxidizing 5. However, the native oxides are hardly removed completely by the (NH 4 ) 2 S solution 6.…”

Improved Electrical Properties of Gd[sub 2]O[sub 3]∕GaAs Capacitor with Modified Wet-Chemical Clean and Sulfidization Procedures

“…34,35 We suggest that the movement of surface Fermi level is related to the actual sulfidation procedure and the resulting sulfur adsorption; the E f intends to shift back to E c provided that more Ga-S bonds form at the interface, 36 for example, which can be obtained after high-temperature annealing. On the as-treated sample the formation of less-stable As-S bonds compared to Ga-S bonds has been deduced to induce the extra gap states; 37 this consequence directly affects the shift behavior of the E f in experiments. In our case, because the interfacial state density ͑D it ͒ was reduced from the order of 10 13 to 10 12 cm −2 eV −1 , we believe that improved WCP, along with relatively more GaS x formation, did facilitate the reduction of overall surface recombination centers, in particular for donors induced by As Ga antisites.…”

Linear- and Geiger-Mode Characteristics of Al0.8Ga0.2As Avalanche Photodiodes

“…To measure the excess noise, a 150 µm-diameter APD was connected through a bias tee to an HP 8970 noise figure The diamond symbols represent measured data and the dashed curves were calculated using a conventional local-field model [17]. meter that was programed to measure at 110 MHz with a band width of 4MHz.…”