SOI Thermal Impedance Extraction Methodology and Its Significance for Circuit Simulation

The buried-oxide in SOI MOSFET inhibits heat dissipation in the Si film and leads to increase in transistor temperature. This paper reports a simple and accurate characterization method for the self-heating effect (SHE) in SOI MOSFET. The ac output conductance at a chosen bias point is measured at several frequencies to determine the thermal resistance ( ) and thermal capacitance ( ) associated with the SOI device. This methodology is important to remove the misleadingly large self-heating effect from the dc – data in device modeling. Not correcting for SHE may lead to significant error in circuit simulation. After SHE is accounted for, the frequency-dependent SHE may be disabled in circuit simulation without sacrificing the accuracy, thus providing faster circuit simulation for high-frequency circuits.