Investigation of Si incorporation in (010) β-Ga2O3 films grown by plasma-assisted MBE using diluted disilane as Si source and suboxide Ga2O precursor

Abstract

Traditionally, elemental Ga and Si have been used to supply Ga and Si, respectively, in molecular beam epitaxy (MBE) to grow Si-doped β-Ga2O3. In this work, we investigated the feasibility of enhancing the β-Ga2O3 growth rate by using a Ga-suboxide precursor in a plasma-assisted MBE. Additionally, Si doping of β-Ga2O3 using diluted disilane and Ga-suboxide as the Si and Ga precursors, respectively, was studied. The growth rate and film quality under different suboxide fluxes were inspected. We found that Si concentration has an inverse relationship with Ga2O flux due to atom competition. A room-temperature mobility of 115 cm2/V s was measured for an electron concentration of 1.2 × 1017 cm−3 on the sample grown using a Ga2O beam equivalent pressure of 1.1 × 10−7 Torr and a disilane flow rate of 0.006 sccm. Temperature-dependent Hall characterization was performed on this sample, revealing compensating acceptor and neutral impurity densities of 2.70 × 1015 and 8.23 × 1017 cm−3, respectively.