The modification of metal/GaAs interfaces by atomic hydrogen has been studied using rf plasma in a reactive ion etching (RIE) system as well as hydrogen generated in an electron cyclotron resonance (ECR) system. Current-voltage (I-V) characteristics of Au/n-GaAs Schottky devices reveal a reduction in the barrier height following the room temperature rf plasma, and a slight increase with ECR hydrogenation at elevated temperatures. More interestingly, a profound increase in the effective barrier height is seen for p-GaAs (from 0.35 to 0.84 eV for the rf plasma and 0.35 to 0.69 eV for ECR). Dopant deactivation close to the surface is observed with spreading resistance and capacitance-voltage (C-V) measurements for both conductivity types. The passivation of existing deep levels and the creation of new deep levels have been found in both H RIE treated and ECR hydrogenated GaAs. The large ideality factor n in I-V plots and large voltage intercept in 1/C2 plots suggest the formation of an insulator-like I layer. The improvement in I-V characteristics for ECR hydrogenated n-GaAs indicates the effect of H passivation on a chemically etched GaAs surface. The recovery of the hydrogenation effects has also been studied as a function of temperature, illumination, and bias-anneal.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)