Low-temperature SOI (Si-on-insulator) formation by lateral solid-phase epitaxy

Low-temperature (550-600 °C) formation of a Si-on-insulator structure by a solid-phase process is investigated. A microprobe (μ) reflection high-energy electron diffraction observation reveals that oriented crystal growth propagates from the seeding area in solid-phase epitaxy (SPE). The effects of random nucleation, epitaxial alignment, and local doping on lateral (L)-SPE are examined. As a result, a relatively large L-SPE area, 14 μm from the seeding area, is achieved on insulating regions. Crystal quality and electrical properties of L-SPE layers are examined using μ-Raman spectroscopy and field-effect transistor fabrication. A small stress field, 2.5×10⁹ dyn/cm², and high electron mobility, 720 cm²/V s, comparable to that of bulk Si are obtained.