Low frequency noise in field-plate multigate AlGaN/GaN single-pole–single-throw RF switches on silicon substrate

Abstract

Field-plate (FP) multigate AlGaN/GaN high electron mobility transistor (HEMT) single-pole–single-throw (SPST) radio-frequency (RF) switches were implemented and studied by performing low-frequency noise measurements for high power switch operations. The measured harmonic power suppression results and low frequency noise spectra of various FP multigate devices were analyzed. The parameters of an OFF-state (gate bias=−5V) small-signal model were individually extracted for FP single-, dual-, triple-, and quadruple-gate switch devices. Under ON-state (gate-bias=0V) operation, the insertion loss performance was slightly low because of the increase in the gate number and ON-state resistance (RON). However, the second and third harmonic suppression ratios were enhanced by 6.5 and 11dBc, respectively, from the single-gate device to the quadruple-gate device. The current noise power spectral density measured as a function of the gate overdrive voltage for various devices at 77–300K also indicated that the FP gate achieved a low surface trap density, which is beneficial for harmonic power suppression in high power applications.