Date of Award

2026-08-01

Degree Name

Master of Science

Department

Electrical Engineering

Advisor(s)

David Zubia

Abstract

Defect characterization in semiconductors relies on locating trap levels through the temperature dependence of carrier emission, which makes the accuracy of the device temperature a limiting factor in every extracted parameter. This work addresses the limitations in the cryogenic electrical characterization system at The University of Texas at El Paso, where Deep-Level Transient Spectroscopy (DLTS) had been established but produced activation energies that disagreed with literature values by as much as 0.33 eV. The discrepancy was traced not to the technique but to the transfer of heat to packaged devices in a probe station designed for on-die measurement. The cryogenic stage was modified with the addition of an aluminum nitride substrate and a copper ring. It was upgraded with a 3D-printed clamp that maintains constant contact pressure on the device under test (DUT). Temperature transfer was validated against a 2N2222 bipolar transistor calibrated at Sandia National Laboratories, reducing the mean deviation between the stage setpoint and the device from 28.5 K to 7.6 K, an improvement of approximately 73%. Repeating the DLTS measurement on the modified system returned activation energies of 0.15, 0.22, and 0.39 eV for the VO, V2(=/-), and V2(-/0) defects in a 3 MeV silicon-irradiated S2386 photodiode, agreeing with literature to within 0.04 eV. Thermal Admittance Spectroscopy (TAS) was then developed as an independent, steadystate technique to cross-validate these results, implemented as a MATLAB module covering modeling, calibration, data acquisition, and Arrhenius analysis. TAS returned activation energies of 0.17, 0.23, and 0.41 eV, agreeing with an independent extraction performed at Sandia National Laboratories to within 0.02 eV, and defect concentrations agreeing to within 28%. Capture crosssections showed substantially larger deviation and are identified as the least reliable extracted viii parameter. The work establishes a validated TAS capability at UTEP and quantifies the temperature accuracy on which both techniques depend

Language

en

Provenance

Received from ProQuest

File Size

88 p.

File Format

application/pdf

Rights Holder

Angel Efren Garcia

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