A New Electrically Detected Magnetic Resonance Approach: Spin Dependent Charg Pumping Applied to the 4H-Silicon Carbide/Silicon Dioxide Interface
Open Access
- Graduate Program:
- Materials Science and Engineering
- Degree:
- Doctor of Philosophy
- Document Type:
- Dissertation
- Date of Defense:
- June 15, 2017
- Committee Members:
- Patrick M Lenahan, Dissertation Advisor
- Patrick M Lenahan, Committee Chair
- Suzanne E Mohney, Committee Member
- Michael T Lanagan, Committee Member
- S Ashok, Outside Member
- Keywords:
- Silicon carbide
- electron paramagnetic resonance
- defects
- interface
- electrically detected mangetic resonance
- nitrogen
- Abstract:
- The objective of this work is to develop and investigate a new electrically detected magnetic resonance (EDMR) technique called spin dependent charge pumping (SDCP) for the investigation of semiconductor/dielectric heterointerfaces. In this work, it is applied to the 4H-SiC/SiO2 interface in 4H-SiC MOSFETs. In chapter 1, background information on 4H-SiC MOSFETs is presented. In chapter 2, background on EDMR and the various EDMR techniques we utilize in this dissertation is presented. In chapter 3, the charge pumping (CP) and SDCP response as a function of some gate waveform parameters is investigated. The SDCP response does not quantitatively follow the CP, as one would expect. That is, when plotted versus charge pumping frequency and gate waveform amplitude, the SDCP amplitude is not proportional to the CP amplitude. The differences observed are explained, at least in part, by coupling of charge carrier spins to the paramagnetic trapping centers. This coupling undoubtedly involves spin diffusion, but other factors may also play a role. In chapter 4, SDCP is utilized with other EDMR approaches to develop a new EDMR approach and investigate the role of nitrogen at the 4H-SiC/SiO2 interface. N alters the interface in many ways. First, it reduces the interface trap density. Second, it alters the energy levels of some the interface traps. Third, it introduces significant disorder to the interface. In chapter 5, SDCP is utilized to address the assumption that carbon dangling bonds dominate the SiC MOSFET interface. It is found the carbon dangling bonds do not play a dominating role at the interface. Chapter 6 discusses a novel approach for near-zero magnetic field spin dependent processes based on SDCP called zero field spin dependent charge pumping. Chapter 7 summarizes the conclusions of the work and offers advice for future works.