Performance evaluation of bulk Si and SOI RF LDMOSFETs for emerging RFIC applications

This paper presents the evaluation of performance of 50 V LDMOSFETS designed in bulk Si and SOI for use in power amplifiers for cellular base stations. SOI technology has been fast emerging as the major technology for RF applications due to its inherent advantages such as lower parasitics, lower on-resistance and better noise immunity. Extensive 2-D simulations on an advanced process and device simulator have been performed to study the carrier dynamics in the LDMOSFET. This allows for a better understanding of the means to reduce the device parasitics, that are a major factor limiting the RF performance of the transistor. A simple circuit model has been developed for the LDMOSFET for use in performing large signal AC analyses for RF characterization. Non-Isothermal simulations on the SOI device have shown that at the feature dimensions under consideration, the self heating does not affect the DC and RF performance significantly.