A Simple Extraction Method of Thermal Resistance in Multifinger GaAs HBT

A novel extraction method to estimate the thermal resistance (R-th) of a multifinger GaAs heterojunction bipolar transistor (HBT) device is presented based on the simplified Fourier's law. By calculating the thermal coupling resistance between the fingers on top of the self-heating thermal resistance, the values of R-th of multifinger devices for various dimensions are accurately calculated while maintaining the simplicity of calculation. To verify the idea, the proposed method is compared with the measurement-based method as well as the analytic methods, such as the finite-element method and the solution of 3-D Laplace's equation. For four-finger HBT devices, the extracted R-th results showed good agreements with the analytic methods within an error of 9% and the measurement-based results with a deviation of 7.4%, thus convincing the usefulness of the proposed method.This work was supported in part by the Human Resources Program in Energy Technology of the Korea Institute of Energy Technology Evaluation and Planning (KETEP), granted financial resource from the Ministry of Trade, Industry & Energy, Republic of Korea under Grant 20154030200730 and in part by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education under Grant 2013R1A1A2013345. The review of this brief was arranged by Editor G. Niu. (Corresponding author: Junghyun Kim.