Influence of Dynamic Access Resistances on the Linearity of Large GaN HEMT Powerbars

This paper presents a study of the dynamic access resistance related nonlinearity of GaN HEMT devices with very large periphery. The bias-dependent access resistance is deembeded to the chip reference plane. Our measurement results show that the bias dependence for such a large device is insignificant, at least within the investigated 2 GHz frequency band. Instead, the main source of nonlinearity is the current source. Quantitatively, linearity measurements reveal a good linear behavior of these devices.