Single crystal semiconductor nanomembranes (NM) are important in various applications such as heterogeneous integration and flexible devices. This paper reports the fabrication of AlGaN/GaN NMs and NM high electron mobility transistors (HEMT). Electrochemical etching is used to slice off single-crystalline AlGaN/GaN layers while preserving their microstructural quality. A double heterostructure design with a symmetric strain profile is employed to ensure minimal residual strain in freestanding NMs after release. The mobility of the two-dimensional electron gas (2DEG), formed by the AlGaN/GaN heterostructure, is noticeably superior to previously reported values of many other NMs. AlGaN/GaN nanomembrane HEMTs are fabricated on SiO2 and flexible polymeric substrates. Excellent electrical characteristics, including a high ON/OFF ratio and transconductance, suggest that III-Nitrides nanomembranes are capable of supporting high performance applications.
Bibliographical noteFunding Information:
This research was supported by the National Science Foundation (NSF) under Award CMMI-1129964. The facilities used were supported by the SEAS cleanroom of Yale University, YINQE, and NSF MRSEC DMR-1119826. Portions of this work were performed in the Wisconsin Center for Applied Microelectronics, a research core facility managed by the College of Engineering and supported by the University of Wisconsin-Madison. The authors acknowledge the use of instrumentation supported by NSF MRSEC DMR-1121288. The authors also acknowledge partial support from National Science Foundation of China under 61604077 and Natural Science Foundation of Jiang Province under BK20140394.