Electrical Characterization Of Defects Introduced During Plasma-Based Processing Of GaAs

Abstract

We report the results of experiments during which epitaxially grown n-GaAs was exposed to He-and SiC1 4 -plasmas at similar sets of well defined RF powers and plasma pressures. To study the defects introduced during these plasma exposured, we employed deep level transient spectroscopy (DLTS). The effect of the plasma etch induced defects on the performance of Schottky barrier diodes (SBDs) fabricated on plasma processed GaAs was evaluated by currentvoltage (IV) and capacitance-voltage (CV) measurements.DLTS revealed that each plasma type (He and SiC1 4 ) introduced its own characteristic set of defects. Some of the defects created during He processing and one defect introduced by SiC1 4 etching had identical electronic properties to those introduced during high energy (MeV) He ion bombardment. SiC1 4 etching introduced only two prominent defects, one of which is metastable with electronic properties similar to a metastable defect previously reported in high and low energy He-ion bombardment of Si-doped GaAs. IV measurements demonstrated that the characteristics of SBDs fabricated on He-ion processed surfaces were very poor compared to those of control diodes (diodes fabricated on surfaces cleaned by conventional wet etching). In contrast, the properties of SBDs fabricated on SiC1 4 etched surfaces were as good as, and in some cases superior to, those of control diodes. SBDs fabricated on annealed (at 450 'C for 30 minutes) He-processed samples exhibited improved but still poor rectification. In contrast, SBDs fabricated on annealed SiCl 4 etched surfaces had virtually the same characteristics as those fabricated on unannealed SiC1 4 etched samples. (a) Electronic

Electrical characterization of defects in SiCl4 plasma-etched n-GaAs and Pd Schottky diodes fabricated on it

“…1 we also show data for SBDs fabricated on GaAs processed with He ions under identical conditions. 8 These SBDs exhibit high series resistances (R s ) and nonlinear forward characteristics, indicating that thermionic emission does not dominate. Clearly, SBDs on SiCl 4 -etched surfaces are superior to those fabricated on He-ion processed surfaces.…”