Electrical Characterization of GaN and SiC Schottky Diodes and Non mechanical beam steering using Liquid Crystals

Open Access
Author:
Kurhade, Kandhar Kantesh
Graduate Program:
Electrical Engineering
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
October 06, 2015
Committee Members:
  • Jerzy Ruzyllo, Thesis Advisor
Keywords:
  • GaN
  • SiC
  • Electrical Characterisation
  • Schottky Diodes
  • Liquid Crystals
  • Beam Steering
Abstract:
In this thesis we investigated the electrical characteristics of GaN schottky diodes fabricated on a commercial LED wafer using Inductively Coupled Plasma Reactive Ion etching (ICP-RIE) techniques. We also researched the characteristics of commercially available SiC schottky diodes. Two main electrical characterization techniques were used in the investigation of these diodes, Current - Voltage Characterization and Capacitance - Voltage Characterization. Using I-V characteristics the ideality and the Barrier height of the Schottky diode was determined and the C-V characteristics were used to calculate the doping concentration of the device. These measurements were done at room temperature as well as different temperatures ranging from 100K to 300K for GaN diodes and 133K to 433K for SiC diodes to observe the dependence of Barrier height and the Ideality factor on the temperature. It was concluded that for GaN the ideality factor decreases with the increase in temperature while the barrier height increases with increase in temperature. The values of barrier height for GaN at 120K is 0.44eV and at 300K it is 0.81eV and the ideality factor at 120K is 0.96 and at 300K it is 0.6. The carrier concentration of the SiC remains constant through the three regions while the carrier concentration of GaN device increases as the reverse bias increases. GaN diode was also measured at two different frequencies to observe if there is any change in the C-V profile and the profile was similar for the two frequencies. Further this thesis comprises of a small novel device which is in the process of fabrication. It is a non-mechanical beam steerer which makes use of Liquid crystals to deviate a beam from its normal position. This thesis only includes the architecture used in the manufacturing of the device and the fabrication of a liquid crystal cell.