New insights into low frequency noise (LFN) sources analysis in GaN/Si MIS-HEMTs

Abstract

We present a thorough investigation of the low frequency (LF) noise in the access and channel regions in GaN MIS-HEMT devices. The 1/f noise behaviour is caused by trapping/de-trapping processes which are well described by carrier number fluctuations (CNF) and correlated mobility fluctuation (CMF) models. To address the issue of LF noise in the access and channel regions of GaN MIS-HEMT devices, we have tested respectively “non-gated” and “gated” devices with different designs. The border trap density extracted in optimized devices at AlGaN/GaN and Al2O3/GaN interfaces is better than previously reported GaN data and close to silicon CMOS results. This enabled us to show a controlled LF noise level and even improved one, emphasizing the progress in the manufacturing process of advanced GaN technologies. Due to the gate channel shape of GaN MIS-HEMT devices with recessed gate, a new CNF/CMF noise model including access resistance noise source is also proposed. It enables a reliable parameter extraction in each channel region, authorizing device noise modeling over a large set of GaN MIS-HEMT process and design.