Characterizing Radiation-Induced Contact Degradation in Silicon Carbide Devices via Electrothermal Simulations
- Ricardo PETERSON
- Ricardo PETERSON (PhD Student, Department of Electrical Engineering)
- Prof. Debbie SENESKY (Stanford University, Department of Aeronautics & Astronautics)
Device reliability is critical to the integrity of electronics systems used in the aerospace industry (e.g. satellites, cubesats, spacecrafts, etc.). In particular, R&D in device reliability is indispensable for electronics operating in harsh environments, such as in Low Earth Orbit (LEO), where particle radiation is prevalent. In particular, radiation-induced degradation at metal-semiconductor (MS) interfaces has been shown to cause device failure. It is therefore crucial to gain insight on the time-dependent distributions of various parameters at irradiated MS interfaces. However, experimentally irradiating and testing electronics is costly and time consuming. Therefore, researchers often resort to simulation techniques to gain insight on how their systems are affected in these harsh environments. In this work, the electrical and thermal effects induced by particle radiation is studied by leveraging the power of GEANT4. Using a custom MATLAB framework, the simulations from GEANT4 are used to locally define generated electron/hole pairs to a high degree of accuracy, and a Finite Element Analysis solver (COMSOL Multiphysics) is used to model the time behavior of the device’s electrical and thermal properties.
Developing device-level solutions that can mitigate contact degradation requires one to have insight on thermal effects at the MS interface, which include the time-dependent electrical field and temperature profiles of an irradiated device. For example, a SiC Schottky diode reverse biased to -100 V, when exposed to radiation, is highly vulnerable to local melting in the Schottky contact (Figure 2).1 Interface temperatures exceeding the melting points of the metal and/or semiconductor will, at best, degrade the interface and thus the material properties of the device, with the potential to cause a Single Event Breakdown.
Furthermore, Single Event Transients can be explicitly studied under any device design and radiation type. Figure 2 depicts an example of this process, where a 1 GeV/n Ar ion penetrates 12 um of Silicon (Si), with two operating N-MOSFETs on the top-left corner, labeled M1 and M2. The GEANT4 data (Fig. 1a) was parsed, processed, and imported into COMSOL Multiphysics (Fig. 2b).
Figure 1. (a) Thermal surface plot of SiC Schottky diode struck by a heavy ion. (b) Temperature profile along the track of the penetrating ion.
Figure 2. (a) Monte Carlo simulation (GEANT4) of 1 GeV/n Ar Ion penetrating Si substrate (b) Imported GEANT4 data into COMSOL Multiphysics simulation of dual-MOSFETs (M1 & M2). Snapshot ~2 ps after Ar ion impact.
Radiation-induced degradation at metal-semiconductor (MS) interfaces has been shown to cause device failure. It is therefore crucial to gain insight on the time-dependent distributions of various parameters, such as the electric field, power density, and temperature, at the MS contact. Developing device-level solutions that can mitigate contact degradation requires one to have insight on the steady-state and transient behavior of irradiated contacts. In this work, the electrical and thermal effects induced by particle radiation is studied by leveraging the power of GEANT4, and using COMSOL Multiphysics to simulate the time-dependent behavior.