Self-aligned formation of the trench bottom shielding region in 4H-SiC trench gate MOSFET

Kojima, Takahito; Harada, Shinsuke; Kobayashi, Yusuke; Sometani, Mitsuru; Ariyoshi, Kingo; Senzaki, Junji; Takei, Masahiro; Tanaka, Yasunori; Okumura, Hajime

doi:10.7567/jjap.55.04er02

Cited by 21 publications

(15 citation statements)

References 33 publications

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“…However, the TMOSFETs suffer reliability issues due to electric field crowding at the gate oxide in the blocking mode. To suppress electric field crowding, various technologies such as bottom protection p-wells (BPWs), bottom thick oxides, double trench structures, and double p-base structures were investigated [6][7][8][9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Analysis of Electrical Characteristics in 4H-SiC Trench-Gate MOSFETs with Grounded Bottom Protection p-Well Using Analytical Modeling

2021

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A new analytical model to analyze and optimize the electrical characteristics of 4H-SiC trench-gate metal-oxide-semiconductor field-effect transistors (TMOSFETs) with a grounded bottom protection p-well (BPW) was proposed. The optimal BPW doping concentration (NBPW) was extracted by analytical modeling and a numerical technology computer-aided design (TCAD) simulation, in order to analyze the breakdown mechanisms for SiC TMOSFETs using BPW, while considering the electric field distribution at the edge of the trench gate. Our results showed that the optimal NBPW obtained by analytical modeling was almost identical to the simulation results. In addition, the reverse transfer capacitance (Cgd) values obtained from the analytical model correspond with the results of the TCAD simulation by approximately 86%; therefore, this model can predict the switching characteristics of the effect BPW regions.

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Section: Introductionmentioning

confidence: 99%

Analysis of Electrical Characteristics in 4H-SiC Trench-Gate MOSFETs with Grounded Bottom Protection p-Well Using Analytical Modeling

2021

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“…Of the various SiC MOSFET structures, gate-trench MOSFETs (UMOSFETs) typically have lower on-state resistance compared to planar MOSFETs (VDMOSFETs). In addition, UMOSFETs have higher channel density and mobility than VDMOSFETs due to their ability to form vertical channels on the trench sidewalls and their ability to reduce cell pitch [3][4][5][6][7]. However, there are two main drawbacks to UMOSFETs.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation Analysis of Switching Characteristics in the Source-Trench MOSFET’s

Cheon

Kim

2020

Electronics

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In this paper, we compare the static and switching characteristics of the 4H-SiC conventional UMOSFET (C-UMOSFET), double trench MOSFET (DT-MOSFET) and source trench MOSFET (ST-MOSFET) through TCAD simulation. In particular, the effect of the trenched source region and the gate trench bottom P+ shielding region on the capacitance is analyzed, and the dynamic characteristics of the three structures are compared. The input capacitance is almost identical in all three structures. On the other hand, the reverse transfer capacitance of DT-MOSFET and ST-MOSFET is reduced by 44% and 24%, respectively, compared to C-UMOSFET. Since the reverse transfer capacitance of DT-MOSFET and ST-MOSFET is superior to that of C-UMOSFET, it improves high frequency figure of merit (HF-FOM: RON-SP × QGD). The HF-FOM of DT-MOSFET and ST-MOSFET is 289 mΩ∙nC, 224 mΩ∙nC, respectively, which is improved by 26% and 42% compared to C-UMOSFET. The switching speed of DT-MOSFET and ST-MOSFET are maintained at the same level as the C-UMOSFET. The switching energy loss and power loss of the DT-MOSFET and ST-MOSFET are slightly improved compared to C-UMOSFET.

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“…The poly-trenched structure was formed using the same process as that for the active region. The newly proposed structures contained heavy doping at the bottom of the trench to reduce the crowding electric field [3][4][5][6][7][8][9][10] and to add a quasi-equipotential region. By varying the trench width and ring space, these structures enable deeper and wider field-spreading profiles at the edge region and improve the breakdown voltage compared to the FFR structure as the same cross-section.…”

Section: Introductionmentioning

confidence: 99%

Study of a SiC Trench MOSFET Edge-Termination Structure with a Bottom Protection Well for a High Breakdown Voltage

et al. 2020

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A novel edge-termination structure for a SiC trench metal–oxide semiconductor field-effect transistor (MOSFET) power device is proposed. The key feature of the proposed structure is a periodically formed SiC trench with a bottom protection well (BPW) implantation region. The trench can be filled with oxide or gate materials. Indeed, it has almost the same cross-sectional structure as the active region of a SiC trench MOSFET. Therefore, there is little or no additional process loads. A conventional floating field ring (FFR) structure utilizes the spreading of the electric field in the periodically depleted surface region formed between a heavily doped equipotential region. On the other hand, in the trenched ring structure, an additional quasi-equipotential region is provided by the BPW region, which enables deeper and wider field-spreading profiles, and less field crowding at the edge region. The two-dimensional Technology Computer Aided Design (2D-TCAD) simulation results show that the proposed trenched ring-edge termination structures have an improved breakdown voltage compared to the conventional floating field ring structure.

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Self-aligned formation of the trench bottom shielding region in 4H-SiC trench gate MOSFET

Cited by 21 publications

References 33 publications

Analysis of Electrical Characteristics in 4H-SiC Trench-Gate MOSFETs with Grounded Bottom Protection p-Well Using Analytical Modeling

Analysis of Electrical Characteristics in 4H-SiC Trench-Gate MOSFETs with Grounded Bottom Protection p-Well Using Analytical Modeling

Numerical Simulation Analysis of Switching Characteristics in the Source-Trench MOSFET’s

Study of a SiC Trench MOSFET Edge-Termination Structure with a Bottom Protection Well for a High Breakdown Voltage

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