4H-SiC MOSFET Threshold Voltage Instability Evaluated via Pulsed High-Temperature Reverse Bias and Negative Gate Bias Stresses

• Published in: Materials Vol. 17; no. 8; p. 1908
• Main Authors: Anoldo, Laura, Zanetti, Edoardo, Coco, Walter, Russo, Alfio, Fiorenza, Patrick, Roccaforte, Fabrizio
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 01.04.2024
• Subjects: 4H-SiC; Bias; Chemical vapor deposition; Cross correlation; Electric fields; Electrons; High temperature; HTGB; HTRB; Injection current; Integrated circuits; Interface stability; Manufacturing; Metal oxide semiconductor field effect transistors; MOSFETs; pMOSFET; pulsed stress; Reliability analysis; Semiconductor chips; Semiconductor doping; Silicon carbide; Silicon dioxide; Simulation; Threshold voltage; threshold voltage instability; Transistors; Trapped charge; threshold voltage instability; pMOSFET; 4H-SiC; HTGB; HTRB; pulsed stress
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma17081908

This paper presents a reliability study of a conventional 650 V SiC planar MOSFET subjected to pulsed HTRB (High-Temperature Reverse Bias) stress and negative HTGB (High-Temperature Gate Bias) stress defined by a TCAD static simulation showing the electric field distribution across the SiC/SiO interface. The instability of several electrical parameters was monitored and their drift analyses were investigated. Moreover, the shift of the onset of the Fowler-Nordheim gate injection current under stress conditions provided a reliable method to quantify the trapped charge inside the gate oxide bulk, and it allowed us to determine the real stress conditions. Moreover, it has been demonstrated from the cross-correlation, the TCAD simulation, and the experimental ΔV and ΔV variation that HTGB stress is more severe compared to HTRB. In fact, HTGB showed a 15% variation in both ΔV and ΔV , while HTRB showed only a 4% variation in both ΔV and ΔV . The physical explanation was attributed to the accelerated degradation of the gate insulator in proximity to the source region under HTGB configuration.