Epitaxial Growth and Properties of GaAs on Magnesium Aluminate Spinel

Abstract

Heteroepitaxial normalGaAs films have been grown by the vapor phase organometallic process on magnesium aluminate spinel substrates prepared by various methods. The effects of variations in growth parameters on the epitaxial normalGaAs film characteristics have been studied. These growth parameters include substrate surface preparation, substrate composition, substrate orientation, growth temperature, gas flows, reactor geometry, and source materials. The substrate orientation and the purity of the source materials were found to play a critically important role in determining both the crystallinity and the electrical properties of the films. Unintentionally doped GaAs films with electron and hole mobilities up to 70 and 100%, respectively, of bulk normalGaAs values were grown in the carrier concentration range 1015–1016/cm3. The epitaxial composites have been characterized by physical and electrical methods. Information on the crystalline perfection, optical properties, and carrier transport characteristics has been obtained.