A technique to produce extremely thin (< 1000 angstrom) silicon on ins
ulator (SOI) films for fully-depleted CMOS fabrication is described. T
he worst-case film thickness uniformity is +/-200 angstrom across a 12
5 mm wafer for a given area factor. This technique utilizes a low temp
erature plasma enhanced chemical vapor deposition of Si3N4 acting as a
chemical-mechanical polish-stop layer. The nitride film thickness is
translated into the SOI by chemical-mechanical polishing.