Analysis of the subthreshold characteristics in AlGaN/GaN HEMTs with a p-GaN gate

• Published in: Microelectronics and reliability 2021-11, Vol.126, p.114302, Article 114302
• Main Authors: Tang, Shun-Wei, Chen, Szu-Chia, Wu, Tian-Li
• Format: Article
• Language: English
• Subjects: Dit; Frequency-dependent C-V; P-GaN/AlGaN/GaN; Subthreshold swing
• ISSN: 0026-2714; 1872-941X
• DOI: 10.1016/j.microrel.2021.114302

In this letter, we analyze the subthreshold characteristics in p-GaN/AlGaN/GaN high electron mobility transistors (HEMTs) with two different Mg flow, i.e., 300 sccm and 750 sccm. The device with 750 sccm Mg flow shows a high threshold voltage and large subthreshold swing (SS). The frequency dependent C-V measurement is reported in p-GaN/AlGaN/GaN heterostructure, showing an obvious frequency dispersion in the device with a high Mg flow. Furthermore, the equivalent circuit network with considering the series of a Schottky metal/p-GaN junction capacitor (CSchottky) and the AlGaN barrier capacitor (CAlGaN) is proposed to calculate the interface state density (Dit) via the conduction method. Finally, a strong correlation between SS, Dit and Mg flow can be concluded, pointing out that the optimization of Mg out-diffusion in p-GaN is crucial to improve the subthreshold characteristics. •The subthreshold characteristics in p-GaNHEMTs with two different Mg flow, i.e., 300 sccm and 750 sccm, are analyzed.•The frequency dependent C–V measurement shows an obvious frequency dispersion in the device with a high Mg flow.•The equivalent circuit network is proposed to calculate the interface state density (Dit) via the conduction method.•A strong correlation between SS, Dit and Mg flow can be concluded.