MICROSCOPIC PROCESSES DURING ELECTRON-CYCLOTRON-RESONANCE MICROWAVE NITROGEN PLASMA-ASSISTED MOLECULAR-BEAM EPITAXIAL-GROWTH OF GAN GAAS HETEROSTRUCTURES - EXPERIMENTS AND KINETIC MODELING/

A set of delta-GaNyAs1-y/GaAs strained-layer superlattices grown on Ga As (001) substrates by electron cyclotron resonance (ECR) microwave pl asma-assisted molecular beam epitaxy (MBE) was characterized by ex sit u high resolution X-ray diffraction (HRXRD) to determine nitrogen cont ent y in the nitrided GaAs monolayers as a function of growth temperat ure T. A first order kinetic model is introduced to quantitatively exp lain this y(T) dependence in terms of an energetically favorable N for As anion exchange and thermally activated N-surface desorption and su rface segregation processes. The nitrogen surface segregation process, with an estimated activation energy E(s) similar to 0.9 eV appears to be significant during the GaAs overgrowth of GaNyAs1-y layers, and is shown to be responsible for strong y(T) dependence. (C) 1996 American Vacuum Society.