SBIR-STTR Award

This Small Business Innovation Research (SBIR) Phase I project will explore an improved process of manufacturing Silicon-on-Insulator (SOI) wafers. The SOI process includes: (1) forming a hydrogen-rich buried layer in a donor silicon wafer; (2) prebonding the donor wafer to a handle wafer; (3) cleaving the donor wafer along the buried layer to thinner top silicon; and (4) postbonding and surface smoothing of the final SOI wafer. An initial wafer is oxidized allowing it to get the buried oxide of SOI. A new feature is an improved activation of wafer surfaces to be bonded. Activation is termination of surfaces with either hydrogen or with hydroxyl groups. Preliminary results show that the terminated surfaces contain more than a monolayer of hydrogen. And the excessive adsorbed hydrogen causes transfer faults during subsequent layer transfer. The Phase I activation process allows control of the hydrogen dose. The process uses radio frequency plasma treatment instead of wet processing. It is expected that the yield of the SOI process will be increased. The new process will be used in the silicon wafer market, which currently totals $10B annually. Estimates indicate that SOI wafers will increase to around 20% of this market within 10 years as SOI is one of the few solutions for production wafers based on less than 0.18 micron design rules.

This Small Business Innovations Research (SBIR) Phase II project builds on demonstrated and patented new hydrogenation-based processes for producing silicon-on-insulator (SOI) wafers for the semiconductor manufacturing industry. It has been demonstrated that this new techniques can be bonded for improved activation of the surfaces of silicon wafers. The innovation also serves to suppress layer transfer faults. The improvement in yield and the reduction in cost in the SOI production process have also been achieved. The process is expected to scale down to the formation of SOI surface films of thickness well below 0.1 micron. During Phase I, an RF plasma treatment was developed which optimizes the amount of adsorbed activating species on surfaces resulting in an improved layer transfer yield over previous wet chemical activation techniques. The process optimization was based on molecular dynamics simulation of the sub-monolayer hydroxylized surface. In Phase II the simulation-based process design continues with experimental characterization of the resulting probability of the layer transfer faults. The Phase II work plan includes more detailed process design and optimization leading to a characterization of best effort SOI wafers by the venture partners. The impact of the proposed commercialization activity on the existing $10B worldwide silicon starting-wafer industry is potentially huge. The increasing usage of SOI by the leading semiconductor manufacturers is optimistically projected to grow from 1% to 10% of the worldwide silicon market. If successful, a ramp up to commercialization SOI pilot production will begin immediately upon the completion of this Phase II contract