Improved Au Schottky contacts on GaAs using cryogenic metal deposition

The use of low temperatures (similar to 77 K) during Au Schottky contact deposition onto n-GaAs produces an increase in barrier height from 0.73 eV for room temperature diodes to 0.82 eV. There is no evidence of drift in the forward current in either type of diode and the low temperature deposited samples show smoother Au layers and more abrupt Au/GaAs interfaces as determined by x-ray reflectivity measurements. Both types of diodes show surface and bulk contributions to the reverse bias current. The diodes with Au deposited at cryogenic temperature did show higher ideality factors, which may result from contaminants gettered to the cold GaAs surface. (c) 2006 American Vacuum Society.