Prediction of submicron junction temperatures in microelectronics using IR techniques

Infrared (IR) techniques can accurately measure temperatures with high spatial resolution, on the order of a few microns resolution. In microelectronics, however, a device’s hot spot, the junction temperature, is a small fraction of a micron. Accurate prediction of junction temperature is critical for reliability and thermal management. This paper presents an accurate closed form model for the junction temperature as a function of device geometry. Based on knowledge of the temperature profile it is possible to reverse the averaging inherent in the IR measurement and obtain the junction temperature accurately based on IR microscopy. This paper illustrates this approach for the case of field effect transistors (FETs) and applies it to several actual measurements.