Fabrication of SOI CMOS over large-area continuous-oxide films formed using epitaxial lateral overgrowth techniques

The authors have developed techniques for producing thin, monocrystalline silicon films over large area continuous oxides using the epitaxial lateral overgrowth (ELO) approach and have investigated the electrical characteristics of CMOS devices fabricated in these films. A conventional ELO process using a growth-etchback technique to eliminate spurious nucleation was used to overgrow single-crystal silicon from seed regions over the oxide stripes. Silicon nitride was deposited and patterned with a mask which had an identical pattern to the first mask. After nitride etch, the original seed region was exposed. A partial silicon etch was performed and the wafers were then reoxidized. During this step an oxide was grown over the exposed seed region which subsequently coalesced with the initial oxide stripes, forming a continuous insulating region covered by stripes of single-crystal silicon. These formed the seed for a second ELO step that resulted in a continuous single-crystal silicon film over the underlying oxide. The transistors, fabricated in ELO material, exhibited electrical characteristics comparable to both SOS controls and to devices fabricated on SIMOX (silicon implanted with oxygen) wafers in the laboratory using an identical process.<
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