Method of making a low dislocation density semiconductor device

Abstract

A low dislocation density semiconductor device includes a first semiconductor layer of a III-V or II-VI semiconductor compound and alloying atoms on a non-metal substrate. The semiconductor compound usually has a large dislocation density. A predetermined position of the alloying atoms in the compound lattice structure can substantially reduce the compound dislocation density. Energy is applied to the alloying atoms so they are at the predetermined positions. The number of alloying atoms causes the semiconductor compound solubility limit to be exceeded. The layer is formed on a substrate of the III-V or II-VI semiconductor, such as gallium arsenide or another semiconductor, such as silicon or on an insulator such as sapphire. In the latter cases, the layer is formed on an intermediate layer having a lattice constant between that of the substrate and semiconductor compound. A second layer is epitaxially deposited on the first layer so both layers have virtually the same lattice constant and dislocation density. The alloying atoms are deposited by different energy assist methods, e.g. by an ion beam that irradiates the substrate, or by an energy assisted organometallic chemical vapor deposition process. The energy assist can be by ionization or optical irradiation causing topical heating of surface atoms deposited by the OMCVD process, without heating of the substrate or the underlying atoms. If the ion beam process is employed, the substrate is annealed such that the alloying atoms move from initial random locations thereof in the compound lattice to the predetermined locations.