Demonstration of SiC-MOSFET Embedding Schottky Barrier Diode for Inactivation of Parasitic Body Diode

Abstract

External Schottky barrier diodes (SBD) are generally used to suppress the conduction of the body diode of MOSFET. A large external SBD is required for a high voltage module because of its high specific resistance, while the forward voltage of SBD should be kept smaller than the built-in potential of the body diode. Embedding SBD into MOSFET with short cycle length increases maximum source-drain voltage where body diode remains inactive, resulting in high current density of SBD current. We propose a MOSFET structure where an SBD is embedded into each unit cell and an additional doping is applied, which allows high current density in reverse operation without any activation of body diode. The proposed MOSFET was successfully fabricated and much higher reverse current density was demonstrated compared to the external SBD. We can expect to reduce total chip size of high voltage modules using the proposed MOSFET embedding SBD.

Review of Silicon Carbide Processing for Power MOSFET

“…However, these diodes result in bipolar degradation and increase on-state power dissipation [155]. To overcome these issues, a different variety of embedded parallel Schottky barrier diodes (SBDs) with SiC MOSFETs has been proposed [156][157][158][159][160][161][162].…”

Conduction Mechanism and Influencing Factors of SiC MOSFET

“…The input capacitance is𝐶 = 𝐶 + 𝐶 , and the output capacitance is 𝐶 = 𝐶 + 𝐶 . [3]. layer, chip solder, and chip.…”

Channel Design Optimization for 1.2-kV 4H-SiC MOSFET Achieving Inherent Unipolar Diode 3rd Quadrant Operation

“…Alternatively, when the unipolar diode structure is integrated within the MOSFET, a significant reduction in wafer area is achieved by sharing active and edge termination areas. Monolithic integration of Schottky or JBS diode in a SiC MOSFET structure (JBSFET) and SiC MOSFET integrating the unipolar internal inverse channel diode were reported earlier [2][3][4][5], respectively. However, JBSFET from [2] on-resistance due to the larger cell pitch from the portion of JBS diode when compared with standalone MOSFET.…”