The Sensitivity of Near-Zero Field Magnetoresistance Measurements

Open Access
- Author:
- Allridge, Elijah
- Graduate Program:
- Engineering Science and Mechanics
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- August 13, 2024
- Committee Members:
- Patrick M Lenahan, Thesis Advisor/Co-Advisor
Suzanne E Mohney, Committee Member
Laura Cabrera, Program Head/Chair
Saptarshi Das, Committee Member - Keywords:
- Spin Dependent Recombination
Silicon
MOSFET
Sensitivity
Electron Paramagnetic Resonance
Electrically Detected Magnetic Resonance
EPR
EDMR
Near-Zero Field Magnetoresistance
NZFMR
SDR - Abstract:
- Near-Zero Field Magnetoresistance (NZFMR) is a new spectroscopic technique for observing electrically active point defects in semiconductor devices. It operates on similar principles to electrically detected magnetic resonance (EDMR), which itself is a derivative of electrically paramagnetic resonance (EPR). Using NZFMR can be advantageous for modern microelectronics due to its simple detection scheme, lower cost of instrumentation, and the ability to perform measurements on commercially packaged devices. While NZFMR lacks some of the analytical power of its complementary techniques, the ease of measuring spin-dependent recombination and spin-dependent trap assisted tunneling, as well as the extractable hyperfine parameters, allows for the technique to be used in a similar way in order to characterize and analyze defects in semiconductor devices. It has been proven effective at observing point defects in devices of numerous material systems, and there is progress being made on the front of modelling the effect as to get more detailed information. While much work has been done on using NZFMR as a characterization technique, there has been virtually no literature on the absolute spin sensitivity of the technique. The goal of this work is to establish a baseline detection floor at which electrically active defects can be detected using this method. This was done using arrays of Si/SiO2 MOSFETs in which the dc I-V gated diode measurement was utilized to count defects, so a precise comparison of interface defect density and NZFMR strength could be. This work shows that NZFMR is at least twice as sensitive as EDMR, which itself is already 100 million times more sensitive than EPR. Better understanding the limitations of the technique will be critical as further studies are performed in order to determine more about the chemical and structural nature of devices.