Events Calendar

MSE Masters Thesis Presentation: Yicong Huang

TITLE: Geant4 simulation of radiation effect on semicondutor matierlas and Hetero-junction Field-Effect Transistor (HFET)

ADVISOR: Enrico Bellotti ECE, MSE

COMMITTEE: Anna Swan ECE, MSE; Masahiko Matsubara

ABSTRACT: Electronic systems operating in the space environment are constantly exposed to high-energy cosmic radiation, ranging from protons to heavy ions, which can deposit significant energy into semiconductor devices and trigger Single Event Effects (SEEs). As Gallium Nitride (GaN) Hetero-junction Field-Effect Transistors (HFETs) become increasingly critical and widely used for high-frequency and high-power applications, establishing a reliable methodology to predict their radiation hardness and failure mechanisms—such as Single Event Burnout (SEB)—is essential. The objective of this thesis is to develop a comprehensive simulation framework that integrates the Geant4 Monte Carlo toolkit with TCAD Sentaurus to accurately model the energy deposition process and its subsequent impact on device operation. The methodology begins with Geant4 simulations of ion-matter interactions, confirming that stopping power increases with both the atomic number of the incident ion and the density of the target material. Subsequently, a Geant4 simulation of a GaN HFET structure is performed to extract a three-dimensional spatial energy deposition profile. These simulations reveal that high-energy ions generate branched tracks due to the significant travel distance of delta electrons, rendering simple linear track assumptions insufficient for accurate modeling. To bridge the gap between particle physics and device simulation, the extracted energy deposition data is converted into electron-hole pair generation rates and mapped into a modified 2D TCAD Sentaurus model. Transient simulations conducted under varying bias conditions exhibit a characteristic double-peak behavior in the drain current following an ion strike. Crucially, the results demonstrate a strong dependence on the operating voltage: at lower drain voltages, the device recovers to its normal off-state (Single Event Transient), whereas at higher voltages, the current continues to rise, leading to potential permanent device failure (Single Event Burnout). This research successfully establishes a multi-physics framework that validates the necessity of accounting for complex 3D energy deposition profiles when analyzing radiation effects in advanced semiconductor devices.