Determination of optimum structure of 4H-SiC Trench MOSFET

Harada, Shinsuke; Kato, Masashi; Kojima, Takahito; Ariyoshi, Kingo; Tanaka, Yasunori; Okumura, Hajime

doi:10.1109/ispsd.2012.6229071

Cited by 40 publications

(15 citation statements)

References 4 publications

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“…The double trench structure with a P + shielding region distributes the high electric field of the gate oxide to P + type doping on the source and gate regions. Therefore, it improves the breakdown voltage characteristics of the device [6]. Its gate P + shielding region also reduces the charge coupling effect between the gate and drain so that the C rss and gate-drain charge (Q GD ) are significantly reduced and have better switching performance [7].…”

Section: Introductionmentioning

confidence: 99%

4H-SiC Double Trench MOSFET with Split Heterojunction Gate for Improving Switching Characteristics

Cheon

Kim

2021

Materials

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In this paper, a novel 4H-SiC split heterojunction gate double trench metal-oxide-semiconductor field-effect transistor (SHG-DTMOS) is proposed to improve switching speed and loss. The device modifies the split gate double trench MOSFET (SG-DTMOS) by changing the N+ polysilicon split gate to the P+ polysilicon split gate. It has two separate P+ shielding regions under the gate to use the P+ split polysilicon gate as a heterojunction body diode and prevent reverse leakage `current. The static and most dynamic characteristics of the SHG-DTMOS are almost like those of the SG-DTMOS. However, the reverse recovery charge is improved by 65.83% and 73.45%, and the switching loss is improved by 54.84% and 44.98%, respectively, compared with the conventional double trench MOSFET (Con-DTMOS) and SG-DTMOS owing to the heterojunction.

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Section: Introductionmentioning

confidence: 99%

4H-SiC Double Trench MOSFET with Split Heterojunction Gate for Improving Switching Characteristics

Cheon

Kim

2021

Materials

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“…Power devices typically feature p-grids inside the device active regions to block the high off-state voltage or to protect certain vulnerable structures [1]. With the key challenges, such as low channel resistance [2], channel mobility [3,4], and oxide reliability [5] being addressed, silicon carbide (SiC) devices are now commercially available from several vendors [6,7]. The SiC devices are widely used in power electronics-for example, SiC transistors adopted as switches in inverter circuit, SiC diodes used in rectifier circuit and as a freewheeling diode in inverter circuit.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Electrical Contacts to p-Grid in SiC Power Devices Based on Charge Storage Effect and Dynamic Degradation

Hua

Wei

2020

Electronics

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P-grid is a typical feature in power devices to block high off-state voltage. In power devices, the p-grid is routinely coupled to an external electrode with an Ohmic contact, but Schottky contact to the p-grid is also proposed/adopted for certain purposes. This work investigates the role of contact to p-grid in power devices based on the commonly adopted technology computer-aided design (TCAD) device simulations, with the silicon carbide (SiC) junction barrier Schottky (JBS) diode as a case study. The static characteristics of the JBS diode is independent of the nature of the contact to p-grid, including the forward voltage drop (VF) and the breakdown voltage (BV). However, during the switching process, a Schottky contact would cause storage of negative charges in the p-grid, which leads to an increased VF during switching operation. On the contrary, an Ohmic contact provides an effective discharging path for the stored negative charges in the p-grid, which eliminates the dynamic degradation issues. Therefore, the necessity of an Ohmic contact to p-grid in power devices is clarified.

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“…The electric field strength in the gate oxide often becomes the bottleneck for SiC power devices nowadays. Thus, a gate oxide electric field smaller than 3 MV/cm is widely required to guarantee the device reliability [32][33][34]. Figure 5 displays the off-state electric field distribution inside the studied P-IGBT, T-IGBT, and the proposed SiC IGBT under V CE = 20 kV and V GE = −5 V. In the P-IGBT, the p-bodies protect the gate bottom from the high off-state collector voltage.…”

Section: Introductionmentioning

confidence: 99%

A New SiC Planar-Gate IGBT for Injection Enhancement Effect and Low Oxide Field

Zhang¹,

Li²,

Zheng³

et al. 2020

Energies

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A new silicon carbide (SiC) planar-gate insulated-gate bipolar transistor (IGBT) is proposed and comprehensively investigated in this paper. Compared to the traditional SiC planar-gate IGBT, the new IGBT boasts a much stronger injection enhancement effect, which leads to a low on-state voltage (VON) approaching the SiC trench-gate IGBT. The strong injection enhancement effect is obtained by a heavily doped carrier storage layer (CSL), which creates a hole barrier under the p-body to hinder minority carriers from being extracted away through the p-body. A p-shield is located at the bottom of the CSL and coupled to the p-body of the IGBT by an embedded p-MOSFET (metal-oxide-semiconductor field effect transistors). In off-state, the heavily doped CSL is shielded by the p-MOSFET clamped p-shield. Thus, a high breakdown voltage is maintained. At the same time, owing to the planar-gate structure, the proposed IGBT does not suffer the high oxide field that threatens the long-term reliability of the trench-gate IGBT. The turn-off characteristics of the new IGBT are also studied, and the turn-off energy loss (EOFF) is similar to the conventional planar-gate IGBT. Therefore, the new IGBT achieves the benefits of both the conventional planar-gate IGBT and the trench-gate IGBT, i.e., a superior VON-EOFF trade-off and a low oxide field.

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Determination of optimum structure of 4H-SiC Trench MOSFET

Cited by 40 publications

References 4 publications

4H-SiC Double Trench MOSFET with Split Heterojunction Gate for Improving Switching Characteristics

4H-SiC Double Trench MOSFET with Split Heterojunction Gate for Improving Switching Characteristics

Investigation of Electrical Contacts to p-Grid in SiC Power Devices Based on Charge Storage Effect and Dynamic Degradation

A New SiC Planar-Gate IGBT for Injection Enhancement Effect and Low Oxide Field

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