Ultra thin SOI material by implantation of nitrogen and diffusion of oxygen to form a buried layer of silicon oxy-nitride

Abstract

An extremely low dose (5E16 cm/sup -2/) of nitrogen ions has been implanted at very low implant energy (25 keV) into silicon to produce ultra thin SOI wafers with a buried layer of silicon oxy-nitride as thin as 43nm and a top silicon layer as thin as 35 nm after high temperature annealing. Such a low dose significantly reduces the implant time which increases the thruput, produces less damage to the silicon which leads to lower defect densities and decreases contamination. This process is very attractive for high volume manufacturing of SOI at a much lower cost compared with SIMOX. This material will be suitable for ULSI CMOS applications where the thickness of the SOI and buried layers are to be 50 nm each. The described method has to be optimized to obtain device quality SOI material.