An accurate method to extract thermal resistance of GaN-on-Si HEMTs

An accurate method to extract the thermal resistance ( R T H ) of GaN-on-Si high electron mobility transistors (HEMTs) is proposed. It is shown that by pulsing the substrate, instead of drain or gate as done in the existing methods, one can significantly reduce the effect of traps on the extraction process. To demonstrate this, HEMTs are fabricated on two wafers, similar in all respects except that one has a carbon-doped buffer and the other does not. We obtain the same value of RTH for the two wafers using the proposed method, while the values are significantly different using the method based on drain pulsing. The extracted RTH is also used in a compact model to demonstrate the accuracy of the proposed method.