SELECTIVE EPITAXIAL FORMATION OF SEMICONDUCTOR FILMS

摘要

Epitaxial layers (125) are selectively formed in semiconductor windows (114) by a cyclical process of repeated blanket deposition and selective etching. The blanket deposition phases leave non-epitaxial material (120) over insulating regions (112), such as field oxide, and the selective etch phases preferentially remove non-epitaxial material (120) while deposited epitaxial material (125) builds up cycle-by-cycle. Quality of the epitaxial material (125) improves relative to selective processes where no deposition occurs on insulators (112). Use of a germanium catalyst during the etch phases of the process aids etch rates and facilitates economical maintenance of isothermal and/or isobaric conditions throughout the cycles. Throughput and quality are improved by use of trisilane, formation of amorphous material (120) over the insulating regions (112) and minimizing the thickness ratio of amorphous:epitaxial material in each deposition phase.