SCALE Dose Enhancement Effects in Nanometer-Scale Technologies

Elliot Wong, a graduate student at Vanderbilt, presented at the Vanderbilt Seminar Series.

Dose enhancement in nanometer‑scale device stacks represents a critical challenge for contemporary microelectronics, where multilayer thin‑film architectures are increasingly vulnerable to ionizing radiation. Understanding how secondary electrons generated by photon interactions deposit energy across material interfaces is essential for predicting device reliability in space, high‑energy physics, and nuclear environments.
The presentation outlines the CARRE collaboration’s investigation of dose enhancement using the CARE framework and Monte‑Carlo simulations performed with the Mr. Ed code. It details the relative contributions of the photoelectric effect, Compton scattering, and pair production—each governed by atomic number and photon energy—to local energy deposition in stacked metals, dielectrics, silicides, and silicon. Angular dependence of the incident radiation is examined by sweeping ion flux from –90° to +90°, revealing pronounced variations in deposited dose within source‑drain, gate‑oxide, and buried‑oxide regions of a 22 nm fully depleted silicon‑on‑insulator (FDSOI) transistor. Three modeling approaches—x‑ray attenuation, continuous energy loss, and energy‑loss fluctuation—are compared, with continuous energy loss identified as the most appropriate for nanometer‑scale geometries where secondary‑electron transport near interfaces dominates.