CONTROLLING OF SCHOTTKY-BARRIER HEIGHTS FOR AU N-GAAS AND TI/N-GAAS WITH HYDROGEN INTRODUCED AFTER METAL-DEPOSITION BY BIAS ANNEALING/

Up to now, in most of the research work done on the effect of hydrogen on a Schottky barrier, the hydrogen was introduced into the semicondu ctor before metal deposition. This letter reports that hydrogen can be effectively introduced into the Schottky barriers (SBs) of Au/n-GaAs and Ti/n-GaAs by plasma hydrogen treatment (PHT) after metal depositio n on [100] oriented n-GaAs substrates. The Schottky barrier height (SB H) of a SB containing hydrogen shows the zero/reverse bias annealing ( ZBA/RBA) effect. ZBA makes the SBH decrease and RBA makes it increase. The variations in the SBHs are reversible. In order to obtain obvious ZBA/RBA effects, selection of the temperature for plasma hydrogen tre atment is important, and it is indicated that 100-degrees-C for Au/n-G aAs and 150-degrees-C for Ti/n-GaAs are suitable temperatures. It is c oncluded from the analysis of experimental results that only the hydro gen located at or near the metal-semiconductor interface, rather than the hydrogen in the bulk of either the semiconductor or the metal, is responsible for the ZBA/RBA effect on SBH.