A new method to extract HBT thermal resistance and its temperature and power dependence

Abstract

This paper introduces a new technique for the measurement of the thermal resistance of HBTs. The method is very simple, because it requires only standard dc I C -V CE measurements taken at different baseplate temperatures, but it is able to account for the dependence of the thermal resistance on both the baseplate temperature and the dissipated power (under the simplifying assumption that the thermal resistance increases linearly with the dissipated power). We have obtained and shown consistent results extracted from devices with an emitter area ranging from 90 µm 2 (1 finger) to 1080 µm 2 (12 fingers). The thermal-resistance values extracted with a standard and wellknown technique are seen to fall inside the range of our results. We have also applied an alternative method that assumes a linear dependence between thermal resistance and junction temperature, and we have shown that both models lead to similar results, which points to the consistency and robustness of our extraction technique.

A review of the use of electro-thermal simulations for the analysis of heterostructure FETs

“…13 shows for five values of power density (from 0.5 · 10 4 W/cm 2 to 1.5 · 10 4 W/cm 2 with a step of 0.25 · 10 4 W/cm 2 ). This finding is consistent with experimental results (see for instance [10]). Simulations and charts such as these are necessary to properly scale the devices and their models.…”

A Scalable Electrothermal Model for Transient Self-Heating Effects in Trench-Isolated SiGe HBTs

“…In fact, intermodulation products generated near the thermal time constant τ thermal can play an important role [7]. Several research studies were performed to study self-heating effects in steady-state [8] and in transient conditions [9], [10] to obtain thermal resistance R TH and thermal capacitance C TH , respectively. The dynamic relationship between instantaneous power dissipation and the temperature rise due to self-heating is incorporated inside a compact model using a passive network.…”

Low-cost and versatile thermal test chip for power assemblies assessment and thermometric calibration purposes

“…Finally, the relationship between dissipated power and temperature increase is not always linear for high dissipated powers, mainly in specific devices with small geometries such as RF transistors [13]. All these limitations are overcome using TTCs because the heating and temperature sensing elements are naturally decoupled.…”