Investigation of MOCVD Growth and Process Conditions on the Efficacy of a Simplified GaAs‐on‐Si Virtual Substrate Approach

The efficacy of metal‐organic chemical vapor deposition (MOCVD)‐based growth for the production of GaAs‐on‐Si virtual substrates following a recently reported process combining low‐temperature growth, thermal cyclic annealing (TCA), and an asymmetric step‐graded filter (ASG) structure is investigated. The impact of multiple process variables—substrate offcut, V/III molecular flux ratio, growth rate, and growth and annealing temperatures—with respect to resultant surface roughness ( R q ) and threading dislocation density (TDD) is examined. Similar trends as those reported for the original molecular beam epitaxy‐based process are observed in R q and TDD for growths on both 2° and 6° offcut substrates. MOCVD process conditions are established for a reduced‐thickness design yielding GaAs virtual substrates on 2° and 6° offcut Si with TDD (≤4.0 × 10 6 cm −2 ) and R q (2.4 and 5.3 nm, respectively), comparable to conventional graded buffers, but with a total III–V thickness of less than 2.0 µm.