Integrated Lateral SBD Temperature Sensor of a 4H-SiC VDMOS for Real-Time Temperature Monitoring

Abstract

The novel integrated temperature sensor of a power 4H-SiC MOSFET for precise real-time temperature monitoring is proposed in this article, in which a lateral Schottky barrier diode (SBD) is embedded. A physical model considering the influence of the lateral-distribution effect and interface states of the lateral SiC SBD is presented to explain the mechanism and direct the design of the sensor. A high degree of linearity ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${R}^{{2}}{)}$ </tex-math></inline-formula> is achieved, and the proposed sensor obtains high design and fabrication tolerance and integration flexibility, namely, a much smaller size is viable. Specifically, the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${R}^{{2}}$ </tex-math></inline-formula> of the fabricated sensor is 0.9999 in the range of 15°–200°. Under the protection of the p-well, the crosstalk value ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text {cross}}{)}$ </tex-math></inline-formula> between the SiC vertical double-diffused metal-oxide-semiconductor field-effect transistor (VDMOS) and sensor is greatly suppressed, and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text {cross}}$ </tex-math></inline-formula> is less than ±1.87° when the VDMOS is switching. Self-heating tests are employed for comparison with the temperature-sensitive electrical parameter (TSEP) method and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RC</i> thermal resistance model method. The proposed sensor has the potential for integration into SiC modules and integrated circuits (ICs) to realize real-time temperature estimation with high precision and low noise.