Thermal Robustness of Silicon-on-Insulator Versus Bulk Material in L-Band RF Power LDMOSFETs

Abstract

A 7.5-V SOI LDMOSFET was fabricated. Using finite-element numerical simulation, a matched device structure was obtained. Then, by making only minor process modifications, an equivalent simulated bulk device was obtained. Complete DC and RF characterization (experimental and simulated) was performed at 25 and 125°C to compare the technologies. The results show the SOI can deliver higher current density, larger transconductance, better forward transmission, and higher maximum stable gain than the bulk device. SOI has improved performance despite self-heating of up to 20°C more than in bulk. These results are encouraging for developing integrated power amplifiers using SOI.