A STUDY OF HIGH-DOSE AS AND BF2 IMPLANTATIONS INTO SIMOX MATERIALS

Thin film, <0.2 mum, SOI layers were implanted with high doses of As a nd BF2 to simulate actual source/drain formation of MOS devices. Elect rical measurements and cross-sectional TEM (XTEM) were used to evaluat e the degree of recrystallization achieved after furnace annealing. BF 2-implanted samples showed complete recrystallization and a high degre e of activation for all examined conditions. XTEM pictures of As-impla nted samples showed polycrystalline structures for higher energies; el ectrical measurements showed increasing sheet resistivity with increas ing implantation energy. Arsenic implantation at elevated substrate te mperature in order to recrystallize the SOI film during implantation w as also studied. XTEM showed no polycrystals or defects, and measured sheet resistivities were comparable to bulk values as indicated by SUP REM3 Simulations. The results of this study are useful when converting an existing NMOS or CMOS process to SIMOX substrates.