Abstract

Understanding the effects of electrochemical passivation on the electronic properties of semiconductor surface states is crucial to semiconductor device fabrication. Previous results indicated that the static electric field across the surface of a semiconductor is substantially modified by hydrogen plasma passivation. As an example, after 30 minutes of passivation, the surface field from n(p)-type GaAs samples has been shown to increase by up to a factor of 2(10). Herein, we report the results of our recent measurements of the transient optoelectronic properties of nitrogen-ion implanted GaAs, where the nitrogen ions served as isoelectronic centers and surface implantation densities ranged from 1x10⁸ cm^-2 to 5x10¹⁵ cm^-2. Optically induced THz electromagnetic radiation and time-resolved photoreflectance (ΔR/R) measurements were made and the results of these two different optoelectronic techniques was compared. Both measurements show strong dependence on implantation density and either technique is a good diagnostic of surface implantation density.

© 1994 Optical Society of America