Study on the Heat Transfer of GaN-Based High Power HEMTs

In this paper, study on the heat transfer of GaN-based high electron mobility transistors (HEMTs) on SiC substrate was carried out utilizing transient thermal analysis method. Gate-source voltage (
${V}_{{\text {gs}}}$
) is used as the temperature sensitive parameter. Linear relationship (
${K}$
factor) between
${V}_{{\text {gs}}}$
and temperature is obtained. It is found that the
${K}$
factor is proportional with drain-source current and does not change with the variation of drain-gate voltage in the linear region of HEMT. We proposed and proved that the
${K}$
factor should be calibrated with HEMT working at linear region to insure the accuracy of subsequent thermal evaluation. Moreover, the temperature rise and thermal resistance keeps as constant when
${K}$
factors were calibrated within the linear region. Transient thermal measurement turns out to be a non-destructive, fast, and precise method for the thermal performance analysis and quality control of the power HEMTs.