Study of GaP Nucleation Layers Grown on Si by Plasma‐Enhanced Atomic Layer Deposition

Abstract

The capability of plasma‐enhanced atomic layer deposition (PE‐ALD) for the formation of GaP nucleation layers on Si substrates for further epitaxial growth is explored. The possibility of epitaxial growth of GaP by metalorganic vapor phase epitaxy (MOVPE) on templates prepared by PE‐ALD GaP/Si is demonstrated. The structural and electronic properties of the interfaces between the GaP nucleation layer and the Si substrate as well as their thermal stability are studied. Initially, the GaP/Si structures obtained by PE‐ALD without additional hydrogen plasma exhibit better photoelectric properties compared with that fabricated with high H2 plasma power that induces the formation of defects in the silicon subsurface layer. Annealing at temperatures of 550–600 °C leads to a decrease in the defect concentration created by the hydrogen plasma. Thus, after annealing, the GaP/Si interfaces fabricated by both types of PE‐ALD processes exhibit similar quality. Thermal treatment of the GaP/Si structures at temperatures of 725–750 °C leads to the diffusion of phosphorus from GaP into Si and to the formation of an isotype n‐GaP/n–p‐Si heterojunction with improved photoelectric properties. High‐temperature stability of the GaP/Si interface fabricated by PE‐ALD is essential for its prospective use for GaP/Si templates.