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State of the art and technological challenges of SiC power MOSFETs designed for high blocking voltages
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| Author(s) |
D. Peters; H. Mitlehner; R. Elpelt; R. Schörner; D. Stephani |
| Abstract |
Normally-off n-type inversion channel mode SiC-MOSFETs blocking voltages between 1200 V and
3000 V are presented and discussed. The on-resistance of a 3kV blocking device with 1.45 mm2 active
area amounts to 3 W at room temperature, corresponding to a specific on-resistance of 45 mWcm2.
This value is taken at 20V gate source voltage corresponding to an electrical field strength in the gate
oxide of 2.6 MV/cm. The 4H SiC MOSFET utilizes a 76 nm thick thermal grown gate oxide and a
polycrystalline silicon gate electrode. This oxide thickness provides a significantly improved
reliability as demonstrated in first reliability tests of 1200V. The temperature coefficient of the onresistance
is positive and allows easy paralleling of these devices. At a drain current of 1 A in on-state
the drain source voltage rises from 3.8 V at 25°C to 5.2 V at a junction temperature of 150°C. The
inversion channel mobility could be improved to 10 cm2 /Vs at room temperature. For this case the
channel resistance still dominates the overall on-resistance but decreases with temperature. At 150 °C
the channel contributes 20% to the on-resistance. In contrast to high voltage silicon MOSFETs the
reverse diode of the SiC MOSFET exhibits excellent switching behavior and might be used as the free
wheeling diode. |
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| Filename: | EPE2003-PP0935 - Peters |
| Filesize: | 285.8 KB |
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| Type |
Members Only |
| Date |
Last modified 2003-10-14 by Unknown |
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