Characterization of GaN-semiconductor device structures for high power and high frequency applications

• Main Author: Marimuthu Tamilmaran
• Other Authors: K Radhakrishnan
• Format: Final Year Project
• Language: English
• Published: 2015
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/62099
• Institution: Nanyang Technological University

Applications in electronic and integrated circuits are mainly supported by the Si-based semiconductor. However, Si-based semiconductor have limitations in its properties that makes it difficult to be used in high-frequency and high-power systems. This caused the rise of GaN as an alternative which proved to have excellent properties such as wide band gap, high electron mobility, high breakdown voltages, mechanical and thermal stability. In high power and high frequency applications, switching speed or power conversion efficiency are crucial. Thus, GaN transistors which has superior electrical properties as well as being economically affordable, are designed to replace MOSFETs in such applications. This project is based on systematic characterization of GaN-based device structures which are grown by molecular beam epitaxy. There are several characterization techniques used such as Atomic Force Microscopy (analysis of surface morphology and roughness), Hall measurement (evaluation of carrier mobility, concentration and sheet resistivity), IV measurement (investigation of current leakage), CV-measurement (analysing of depth profiles of carrier concentration and capacitance-voltage) and X-ray diffraction (analysis of layers grown composition and structural properties). The parameters such as metal flux, AlN thickness, substrate temperature are varied accordingly to optimize the growth of GaN based device structures to get good 2DEG properties.