Use of zone-melting recrystallization to fabricate a three-dimensional structure incorporating power bipolar and field-effect transistors

Three-dimensional (3-D) structures have been fabricated incorporating power bipolar transistors in a Si substrate and metal-oxide-semiconductor field-effect transistors (MOSFET´s) in an overlying silicon-on-insulator (SOI) film that was zone-melting recrystallized with a graphite strip heater. Both N-P-N and P-N-P bipolar transistors were used. The N-P-N devices exhibited no significant change in transistor characteristics after zone-melting recrystallization (ZMR), while the P-N-P devices showed a substantial reduction in breakdown voltage. The MOSFET´s exhibited electron mobilities comparable to those in similar devices fabricated in single-crystal Si wafers. The bipolar transistor yield is approximately 90 percent. The unusually high device quality and yield for 3-D structures obtained by the ZMR technique demonstrates the feasibility of fabricating monolithic structures incorporating both logic functions and relatively high-current high-voltage power switches.