Silicon carbide UMOSFET device integrated with SBD, and preparation method thereof

Abstract

The invention provides a silicon carbide UMOSFET device integrated with an SBD, and a preparation method thereof. The device comprises third metal, an N+ substrate and an N- epitaxial layer from bottom to top, and the N- epitaxial layer is provided with a first P- well region, a first N+ injection region, a first P+ injection region, a second P+ injection region, a first groove and a second groove. The device further comprises a first metal, wherein the first metal covers part of the upper surface of the first N+ injection region, the side surface of the first P- well region and the upper surface of the second P+ injection region to form ohmic contact; and a second metal, wherein the second metal covers the upper surface of the first interval to form Schottky contact. According to the silicon carbide UMOSFET device integrated with the SBD, an additional Schottky diode is integrated, so that the follow current capability of the device is improved; and meanwhile, the electric field concentration phenomenon at the left and right groove corners of the gate oxide layer is effectively shielded or relieved by utilizing the deep P+ shielding region and the P+ injection region partially surrounding the groove corners, so that the reverse voltage endurance capability and the use reliability of the device are improved.

Description

【Technical field】 [0001] The invention relates to a silicon carbide UMOSFET device integrating SBD and a preparation method thereof. 【Background technique】 [0002] In recent years, with the continuous development of power electronic systems, higher requirements have been placed on the power devices in the system. Silicon (Si)-based power electronic devices have been unable to meet the requirements of system applications due to the limitations of the material itself. [0003] As a representative of the third-generation semiconductor material, silicon carbide (SiC) material is far better than silicon material in many characteristics. As a commercialized device in recent years, silicon carbide MOSFET devices have great potential to replace existing IGBTs in terms of on-resistance, switching time, switching loss and heat dissipation performance. [0004] However, due to the large bandgap of silicon carbide materials, the turn-on voltage of the parasitic PiN diodes integrated ...

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Problems solved by technology

[0004] However, due to the large bandgap of silicon carbide materials, the turn-on voltage of the parasitic PiN diodes integrated in silicon carbide MOSFET devices is mostly around 3V, which cannot provide freewheeling effects for silicon carbide MOSFET devices themselves.

Therefore, in power electronic system applications such as full bridges, it is often necessary to connect a Schottky diode in antiparallel as a freewheeling diode, which greatly increases the area of ​​the system.

In addition, since the gate oxide layer has a trench-shaped configuration, the electric field concentration generated at the corner is larger than that in the drift region of the device, so that the gate oxide layer may be broken down before the breakdown occurs in the body region, which greatly affects device reliability

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