Local thermal effects in high performance bipolar devices/circuits

Self-heating effects in high-performance bipolar devices and circuits are discussed. A transistor model with self-heating effects, circuit simulation results with and without self-heating, and transient thermal measurements are presented. The relatively large thermal spreading resistance associated with the small device sizes used in VLSI and higher levels of integration in conjunction with the high power levels used in these devices give rise to large thermal gradients between devices within the same circuit. This is shown to result in an additional small (1% to 4%) delay component in a typical CSEF circuit. Larger delay is expected for certain circuits with devices operated at high power densities