A Complementary Metal Oxide Semiconductor Process in Epitaxially Regrown Silicon over Oxide

Abstract

A new solid‐phase epitaxy technique, solid‐phase isolated regrowth for radiation‐immune technology (SPIRRIT), is described that has speed, density, and radiation‐immunity advantages over bulk Si circuit technologies. Partial isolation between source and drain areas and substrate is achieved by incorporating a buried oxide layer into the metal oxide semiconductor (MOS) structures during complementary metal oxide semiconductor (CMOS) processing. Seeded epitaxial regrowth of an amorphized silicon film creates the active transistor channels. Rutherford backscattering and x‐ray diffraction measurements indicate that the current amorphization and recrystallization process yields crystalline material to a depth of 0.2 μm, with some residual subsurface damage in the depth range from 0.2 to 0.5 μm. PMOS SPIRRIT transistors have demonstrated near‐bulk performance. NMOS SPIRRIT transistors displayed high transconductances, but also exhibited large leakage currents. The leakage is attributed to a spurious donor region in the recrystallized film.