Improvement of large area homogeneity of InP based III-V layers by using the gas foil rotation concept

Abstract

Further improvement of thickness and compositional homogeneity was sought in order to increase the usable wafer area for sophisticated device production and thus reduce the manufacturing costs in low-pressure metalorganic vapor-phase epitaxy processes. The gas-foil concept for wafer rotation was used to achieve these goals. In this technique the substrate is placed on a graphite carrier floating on a gas foil (high-purity H/sub 2/). The same gas flow also forces the carrier to rotate. The thickness uniformities of InP, GaInAs and GaInAsP layers grown with the gas-foil rotation susceptor in a single-wafer reactor were better than +or-1.5%. The variation of lattice mismatch of ternary and quaternary layers was below 2.5*10/sup -4/. The GaInAsP wavelength variation was smaller than 4 nm over the entire wafer area (a rim of 5 mm excluded).<>