SELF-HEATING EFFECTS IN SOI MOSFETS AND THEIR MEASUREMENT BY SMALL-SIGNAL CONDUCTANCE TECHNIQUES

Self-heating is an important issue for SOI CMOS, and hence, so is its characterization and modeling, This paper sets out how the critical pa rameters for modeling, i.e., thermal resistance and thermal time-const ants, may be obtained using purely electrical measurements on standard MOS devices, A summary of the circuit level issues is presented, and the physical effects contributing to thermally related MOSFET behavior are discussed. A new thermal extraction technique is presented, based on an analytically derived expression for the electro-thermal drain c onductance in saturation, Uniquely, standard MOSFET structures can be used, eliminating errors due to additional heat flow through special l ayouts, The conductance technique is tested experimentally and results are shown to be in excellent agreement with thermal resistance values obtained from noise thermometry and gate resistance measurements usin g identical devices, It is demonstrated that the conductance technique can be used confidently over a wide range of bias conditions, with bo th fully and partially depleted devices.