Browsing by Author "Meneghesso, Gaudenzio"

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Investigation of the degradations in power GaN-on-Si MIS-HEMTs subjected to cumulative gamma-ray irradiation
(2019-09-01)
Sharma, Chandan
;
Modolo, Nicola
;
Chen, Hsi-Han
;
Tseng, Yang-Yan
;
Tang, Shun-Wei
In this work, GaN-on-Si power Metal-Insulator-Semiconductor High Electron Mobility Transistors(MIS-HEMTs) are irradiated through different regimes of cumulative gamma-ray irradiation, namely 1, 2, 3, 4, and 5 kGy for the first sample; 1, 3, and 5 kGy for the second sample; 1, 5, and 10 kGy for the third sample; and 1, 10, and 20 kGy for the fourth sample. After each irradiation dose, drain current (ID), threshold voltage (I-g), and gate leakage current (Is) are electrically characterized in all the samples. An improvement in I-D with a shift in V-Th is observed in all the samples, which saturates after a higher irradiation dose. X-ray photoelectron spectroscopy (XPS) analysis confirms creation of nitrogen vacancies that act as donor and improves the I-D. No significant change in I-g is observed except for an increase in noise in gate leakage current. Scanning electron microscopy (SEM) shows the Al-based metallization pad degrades due to formation of small cavities. Finally, energy dispersive X-ray (EDX) analysis confirms the formation of Al native oxides due to gamma-ray irradiation.
Understanding gamma-Ray Induced Instability in AlGaN/GaN HEMTs Using a Physics-Based Compact Model
(2020-03-01)
Sharma, Chandan
;
Modolo, Nicola
;
Wu, Tian-Li
;
Meneghini, Matteo
;
Meneghesso, Gaudenzio
In this article, we demonstrate that a physics-based compactmodel can facilitate to analyze the reliability using an example of gamma-ray induced instability in AlGaN/GaN HEMTs. First, the typical AlGaN/GaN HEMTs are subjected to the cumulative gamma-ray irradiation, exhibiting the drain current (I-D) increase. In order to further elucidation, the root cause, the compact model is implemented and calibrated with the pristine case. Then, I-D-V-G and I-D-V-D characteristics subjected to the gamma-ray irradiation are fitted with the compact model. The extracted mu and R-c are consistent with the results obtained by the Hall measurement and circular transmission line measurement (C-TLM). By comparing the fitted curves with considering: 1) fitted mu (R-c is fixed as the pristine case) and 2) fitted R-c (mu is fixed as the pristine case), the shift of mu is identified as the root cause leading to the I-D increase because of the better fitting results. Therefore, with the assistance of the physics-based compact model, the shift of the parameter can be further analyzed to understand the origin of the instability.