A SiC Trench MOSFET concept offering improved channel mobility and high reliability

This work discusses the challenges in the design of a SiC Power MOSFET compared to their silicon-based relatives and describes a novel SiC Trench MOSFET concept. The most prominent difficulties being identified are related to the properties of the channel and the gate dielectric as well as their interface. Different approaches to realize a SiC MOSFET are briefly discussed and the CoolSiC™ MOSFET concept is introduced which balances low conduction losses with an IGBT-like reliability. Long term gate oxide tests reveal that the extrinsic failure rate can be confidently predicted to be less than 1 FIT per die in 20 years under specified use conditions for industrial applications.

[1]  Anant K. Agarwal,et al.  Status of SiC Power Devices and Manufacturing Issues , 2006 .

[2]  N. Sugiyama,et al.  Relation between Defects on 4H-SiC Epitaxial Surface and Gate Oxide Reliability , 2013 .

[3]  Yukiharu Uraoka,et al.  Increased Channel Mobility in 4H-SiC UMOSFETs Using On-Axis Substrates , 2007 .

[4]  Tsunenobu Kimoto,et al.  Interface Properties of Metal–Oxide–Semiconductor Structures on 4H-SiC{0001} and (1120) Formed by N2O Oxidation , 2005 .

[5]  Anders Lindgren,et al.  1200V 6A SiC BJTs with very low VCESAT and fast switching , 2010, 2010 6th International Conference on Integrated Power Electronics Systems.

[6]  Keiji Wada,et al.  The optimised design and characterization of 1200 V / 2.0 mΩ cm2 4H-SiC V-groove trench MOSFETs , 2015, 2015 IEEE 27th International Symposium on Power Semiconductor Devices & IC's (ISPSD).

[7]  J. McPherson,et al.  UNDERLYING PHYSICS OF THE THERMOCHEMICAL E MODEL IN DESCRIBING LOW-FIELD TIME-DEPENDENT DIELECTRIC BREAKDOWN IN SIO2 THIN FILMS , 1998 .

[8]  J. Lutz,et al.  Breakdown of gate oxide of 1.2 kV SiC-MOSFETs under high temperature and high gate voltage , 2016 .

[9]  Daniel Domes,et al.  Switching performance of a 1200 V SiC-Trench-MOSFET in a low-power module , 2016 .

[10]  D. Peters,et al.  Strategic Considerations for Unipolar SiC Switch Options: JFET vs. MOSFET , 2007, 2007 IEEE Industry Applications Annual Meeting.

[11]  A. Hefner,et al.  Reliability of SiC MOS devices , 2004 .

[12]  Gregor Pobegen,et al.  On the Origin of Threshold Voltage Instability under Operating Conditions of 4H-SiC n-Channel MOSFETs , 2016 .

[13]  Jack C. Lee,et al.  Modeling and characterization of gate oxide reliability , 1988 .

[14]  Dimitris E. Ioannou,et al.  Modeling Early Breakdown Failures of Gate Oxide in SiC Power MOSFETs , 2016, IEEE Transactions on Electron Devices.

[15]  H. Sakairi,et al.  High performance SiC trench devices with ultra-low ron , 2011, 2011 International Electron Devices Meeting.

[16]  Richard K. Williams,et al.  The Trench Power MOSFET—Part II: Application Specific VDMOS, LDMOS, Packaging, and Reliability , 2017, IEEE Transactions on Electron Devices.

[17]  T. Hatakeyama,et al.  Microscopic Examination of SiO2/4H-SiC Interfaces , 2011 .

[18]  W. Weibull.  A Statistical Distribution Function of Wide Applicability , 1951 .

[19]  K. Ino,et al.  1200V 4H-SiC Trench Devices , 2014 .

[20]  Kenji Fukuda,et al.  Gate-Area Dependence of SiC Thermal Oxides Reliability , 2008 .

[21]  T. Grasser,et al.  On the subthreshold drain current sweep hysteresis of 4H-SiC nMOSFETs , 2016, 2016 IEEE International Electron Devices Meeting (IEDM).

[22]  Gate Oxide Long-Term Reliability of 4H-SiC MOS Devices , 2010 .