研究目的
To study the stability of threshold voltage in 1200V 4H-SiC MOSFETs, investigate the mechanism of threshold voltage drift due to interface and near-interface traps, and compare with commercial devices.
研究成果
The fabricated 1200V 4H-SiC MOSFETs exhibit excellent threshold voltage stability with minimal shift after 1000 hours of HTGB testing, outperforming commercial devices. The instability is attributed to electron capture by interface and near-interface traps, and the developed model provides insights into the mechanisms involved.
研究不足
The study is limited to specific stress conditions (gate bias and temperature) and may not cover all operational scenarios. The comparison with commercial devices is based on a small sample size, and the model assumptions (e.g., trap densities) might not fully represent real-world variations.
1：Experimental Design and Method Selection:
The study involved designing and fabricating 1200V 4H-SiC MOSFETs, followed by high-temperature gate bias (HTGB) testing to assess threshold voltage stability under stress conditions. A tunneling model was used to simulate charge trapping mechanisms.
2：Sample Selection and Data Sources:
Ten fabricated devices were packaged in TO258 packages for testing. Commercial devices from three companies (C, R, S) were also tested for comparison under the same conditions.
3：List of Experimental Equipment and Materials:
Devices were fabricated using n+ type 4H-SiC substrates, drift layers, implanted regions (Al and N), gate oxide, Ni contacts, PECVD oxide, and Al overlayers. Testing involved applying constant gate voltages and measuring threshold voltage.
4：Experimental Procedures and Operational Workflow:
Devices were stressed at a constant gate bias of +20V or -10V with source and drain grounded at 150°C for up to 1000 hours. After cooling, threshold voltage was measured at Ids = 0.5 mA. Simulations were conducted using a tunneling model with specified trap densities and distributions.
5：5 mA. Simulations were conducted using a tunneling model with specified trap densities and distributions.
Data Analysis Methods:
5. Data Analysis Methods: Threshold voltage shifts were monitored and compared. The tunneling model involved numerical methods to calculate electric fields and trap occupations over time.
独家科研数据包，助您复现前沿成果，加速创新突破
获取完整内容
