Impact of chamber pressure and Si-doping on the surface morphology and electrical properties of homoepitaxial (100) β-Ga2O3 thin films grown by MOVPE

The influence of chamber pressure and Si-doping on the growth rate, surface morphology and Hall mobility was investigated for beta-Ga2O3 thin films homoepitaxially grown by metalorganic vapor phase epitaxy on Mg-doped beta-Ga2O3 (100) substrates with 4 degrees miscut. Transitions from step-bunching to step-flow to 2D island growth modes were achieved by varying the chamber pressure from 10 mbar to 40 mbar and/or by varying the O-2/Ga ratio. High-quality beta-Ga2O3 homoepitaxial thin films with a high electron mobility of 153 cm(2) Vs(-1) have been obtained at a chamber pressure of 25 mbar and a growth rate of 3.6 nm min(-1). The Si-doped films show electron concentrations in the range of 1 x 10(17) to 2 x 10(19) cm(-3). When increasing the chamber pressure to 40 mbar step-flow growth mode and high charge carrier mobility can only be preserved by adjusting the O-2/Ga ratio and increasing the Ar push gas flow. Secondary ion mass spectrometry and Hall measurements for Si and electron concentration, respectively, revealed Si compensation at higher tetraethyl orthosilicate flux.

Automated summary

The study investigated the impact of chamber pressure and Si-doping on the growth of beta-Ga2O3 thin films, resulting in changes in growth modes and electron mobility. High-quality homoepitaxial thin films of beta-Ga2O3 were obtained under optimal conditions.