Gas source molecular beam epitaxy of GaxIn1−xPyAs1−y

Abstract

The use of P₂ and As₂ beams generated by several different beam sources for the growth of InP, GaAs, and Ga_xIn_1−xP_yAs_1−y has been investigated. Accommodation coefficients for As₂ and P₂ were determined for heated GaAs and InP surfaces. It is demonstrated that a source utilizing decomposition of the hydrides over the range 200–2000 Torr and providing a leak of the resulting P₂, As₂, and H₂ molecules into a molecular beam epitaxy (MBE) system can be used for the growth of Ga_xIn_1−xP_yAs_1−y layers lattice matched to InP. Heterostructure lasers emitting at 1.5 μm with room temperature threshold current densities of 2000 A/cm² and differential quantum efficiencies of 17%–19% were fabricated to demonstrate the quality of the epitaxy by this method. Initial studies of the cracking of AsH₃ and PH₃ at low pressures in contact with heated Ta suggest that Ta acts as a catalyst for the decomposition and that low pressure beam sources may also be useful for gas source MBE.