DC Characterization and Validation of the Improved Analytical Model of AlGaN/GaN HEMT

Abstract

Research is being conducted for a high-performance building block for high frequency applications that combine lower costs with improved performance and manufacturability. Researchers have focused their attention on wide band gap (WBG) semiconductor materials for use in device technology to address system improvements. Of the contenders, silicon carbide (SiC), gallium nitride (GaN), and diamond are emerging as the front-runners. The objective of this paper is to demonstrate the DC characterization of high electron mobility transistor (HEMTs) with a focus on gallium nitride process in relevant high frequency applications. The transfer properties of the HEMTs in gallium nitride process are studied by characterizing the two dimensional electron gas (2DEG) and spontaneous and piezoelectric polarization induced charges. The research involves test, characterization and validation of the improved analytical model for the AlGaN/GaN HEMT. The DC characterization includes the measurement of device output characteristics (Ids vs Vds) and transfer characteristics (Ids vs Vgs). These GaN HEMTs demonstrate excellent DC capabilities and can cause electric fields up to 3 MV/cm in group III-nitride crystal. For achieving design success it is very important to develop an accurate empirical and analytical model of the device. A custom DC measurement system is used to facilitate the DC characterization of the unpackaged GaN HEMT test device. The experimental results are in close agreement with the simulation results. The experimental results measured in this research will not only help the GaN device researchers in the device behavioral study but will also provide valuable information for wide band gap (WBG) semiconductor researchers as well as circuit designer.