Enhanced performance of ultraviolet AlGaN/GaN photo-HEMTs by optimized channel isolation schemes

• Main Authors: Mondal, Ramit Kumar, Xiong, Zhongshu, Ghimire, Mohan Kumar, Lingaparthi, Ravikiran, Nethaji, Dharmarasu, Radhakrishnan, K., Kim, Munho
• Other Authors: School of Electrical and Electronic Engineering
• Format: Article
• Language: English
• Published: 2024
• Subjects: Engineering; AlGaN/GaN; UV photodetector
• Online Access: https://hdl.handle.net/10356/174662; https://api.elsevier.com/content/abstract/scopus_id/85187105335
• Institution: Nanyang Technological University

Solar blind ultraviolet (UV) photodetectors utilizing AlGaN/GaN high electron mobility transistor (HEMT) structure offer a very high responsivity, photo-to-dark current ratio (PDCR), and detectivity. However, the performance of conventional mesa-isolated photo-HEMT is limited due to current leakage paths through the side wall and AlGaN barrier. In this work, apart from conventional mesa-type isolation, ion implantation and metal-insulator-semiconductor (MIS) schemes are adopted to isolate the channels of AlGaN/GaN photo-HEMTs. A significant reduction in dark current is achieved for MIS photo-HEMT of around four and three orders of magnitude as compared to those of conventional mesa- and ion-implanted photo-HEMTs, respectively. Moreover, the responsivity and PDCR of MIS photo-HEMT are around three and four orders of magnitude higher than those of conventional mesa-isolated photo-HEMT. Subsequently, MIS photo-HEMT on Si substrate has achieved a very high detectivity of 4.63 × 1016 Jones at the UV incidence wavelength of 360 nm. The results presented in this work establish the advantages of MIS photo-HEMT over other types of photo-HEMTs. In addition, compatibility with GaN device fabrication technology and significantly enhanced optoelectronic performance suggest AlGaN/GaN MIS photo-HEMTs as a promising candidate for a variety of advanced UV sensing applications.