Ion beam processing and rapid thermal annealing of InP and related compounds

Abstract

The use of ion implantation to create doped regions or high-resistivity layers in InP, InGaAs and AlInAs is reviewed. Recent results on carbon implantation into these materials show that it behaves predominantly as a donor in InP but can give rise to p-type doping levels above 10/sup 19/ cm/sup -3/ in InGaAs and AlInAs. The diffusivity of carbon in all of these materials is measured at 800 degrees C. The use of a SiC-coated graphite susceptor provides degradation-free rapid thermal annealing of the In-based III-V semiconductors for high-temperature implant activation. Smooth, residue-free dry etching of these materials is obtained using CH/sub 4//H/sub 2/ mixtures. The use of microwave (2.45 GHz) electron cyclotron resonance (ECR) discharges minimizes the depth of lattice disorder resulting from dry etching, relative to conventional RF discharges. The characteristics of ion milling of InP are reviewed. It is seen that postmilling annealing cannot restore the rear-surface crystallinity after 500 eV Ar/sup +/ ion bombardment of InP, and wet chemical removal of approximately 650 A is necessary.<>