Coprecipitation of Ga[sub 2]O[sub 3] in the Liquid-Phase Epitaxial Growth of GaP

Abstract

Coprecipitation of β‐Ga2O3 has been observed in O‐doped normalGaP epitaxial films grown by liquid‐phase epitaxy under isothermal conditions at an average growth temperature of ∼1040°C. The coprecipitation seems to be independent of cooling rate and of the source of O [ Ga2O3 powder, bulk Ga2O3 , or glassy normalZnfalse(PO3)2 ]. The coprecipitation of β‐Ga2O3 could be prevented either by imposing a temperature gradient over the ampoule (to enhance vapor transport via Ga2O ) or by reducing the amount of O added to the Ga‐rich solution in an isothermal system to ∼2.5×10−2 normala/normalo false(normalatom per centfalse) . The latter result is interpreted as giving the solubility at ∼1040°C of Ga2O3 in Ga saturated with normalGaP and is used to obtain an estimate of the eutectic valley in the ternary normalGa‐P‐Ga2O3 system.

Determination of the Solidus and Gallium and Phosphorus Vacancy Concentrations in GaP

“…In particular, the thermodynamic properties, liquidus curve, and pressure-temperature boundary of GaP have been critically evaluated (1). In addition, by means of experimental and/or theoretical investigations of the ternary liquidus surface (2)(3)(4)(5) and solid solubilities (6-10), a satisfactory understanding of impurity incorporation in GaP has been achieved for such electrically important impurities as Zn (6,7), Te (8), O (5,8,9), and N (I0). However, on account of experimental difficulties, the departure from stoichiometry of GaP represented by the solidus curve and the closely related absolute phosphorus and gallium vacancy (Vp and VGa) concentrations have not yet been determined.…”