Epitaxial growth of InP and related alloys

Abstract

InP has emerged as the third most important semiconductor in the world after Si and GaAs. Since devices invariably require multilayer heterostructures, considerable attention has also been focussed on development of InP-based materials. The utilization of such materials for devices (see Table 1) has increased manifold in recent years not only due to significant advances in epitaxial growth technology but also due to the fact many of their properties are superior to those of Si and GaAs based materials. The superiority of InP due to higher maximum electron drift velocity, peak-to-valley ratio, thermal conductivity and breakdown field, lower ionization coefficient and dielectric constant, MIS structures having low interface state densities, no intrinsic surface states within bandgap, more radiation resistant, etc. over GaAs has already been established for certain device applications. It can be seen from Table 1 that potential applications of InP related alloys have been in the field of microwave, millimeter-wave, ultra-high speed and optoelectronic devices. Such applications have, however, placed stringent demands (i.e. ability to grow high purity and device quality layers, to grow thin and ultra-thin layers with high degree of uniformity in layer thickness, doping and composition and of growing in-situ heterolayers) upon epitaxial growth technology. Keeping these demands in view, an attempt is made in this article to review the salient features of, and recent advances in, various epitaxial growth techniques used for growing InP and lattice matched InP-based materials.