Growth by molecular beam epitaxy and electrical characterization of Si-doped zinc blende GaN films deposited on β-SiC coated (001) Si substrates

Abstract

We report the electrical characteristics of heavily Si‐doped zinc blende GaN epilayers deposited on β‐SiC coated (001) Si substrates. The β‐GaN films were grown by molecular beam epitaxy using a rf plasma discharge, nitrogen free‐radical source, and the doping concentration in the films was controlled over the range 1.5×10¹⁸–3.0×10²⁰ cm⁻³ by suitably adjusting the temperature of a Si effusion cell. We have found that Si incorporation in β‐GaN results in a relatively deep donor level (∼62 meV below the conduction band edge at a carrier concentration at room temperature of 10¹⁸ cm⁻³). Also, we present evidence of simultaneous high mobility conduction band conduction (dominant at high temperatures) and low mobility impurity band conduction (dominant at temperatures n_RT≳10¹⁹ cm⁻³) material.