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Power MOSFETs on SiC have also been the subject of extensive research

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jun sakura

Operable SiC devices have been successfully fabricated in α-SiC in concentrated efforts to develop this material as a semiconductor (Campbell and Chang 1978). However, the devices were produced in Lely crystals, the character of which was not reproducible from run to run, as indicated above. Significant progress has been made regarding the development of these devices, as described below.  https://www.hslabrasive.com/products/silicon-carbide/

The reader is referred to the website  by the SiC power-device research group at Purdue University where one can obtain both continually updated information regarding SiC devices and links to other sources of information regarding SiC-based devices.

The fundamental reasons for the interest in SiC as a potential material for devices, specifically high-temperature and high-power devices, stem from its superior thermal conductivity and thermal stability relative to other semiconductor materials and from the fact that the specific on-resistance of a SiC power device is expected to be 100–200 times lower than a similarly rated silicon device (Baliga 1989). The chemistry, microstructure, and electrical properties of cobalt, titanium, and platinum Schottky contacts on 6H-SiC have been reported (Porter et al. 1995a, 1995b, 1995c). A critical review of the status of contacts to various polytypes has also been published (Porter and Davis 1995). Devices using these types of contacts and known as Schottky diodes are expected to find use as flyback rectifiers in power systems driving inductive loads. Nickel and titanium Schottky diodes (rectifiers) have been fabricated on 4H-SiC (Schoen 1997). The measured blocking voltage of the nickel diode was 1720 V with a specific on-resistance of 5.6 mΩcm2. This former value is approximately 90% of the theoretical plane-junction value, and the latter value is only several times more than the theoretical minimum for this device. It should be noted that Schottky diodes on silicon are limited to applications with a blocking voltage less than 200 V.

Thyristors, or semiconductor-controlled rectifiers (SCRs), are used in a.c. switching applications where they provide both forward and reverse blocking capacities. The first SiC thyristors were fabricated on p-type 6H substrates and had blocking voltages of 50 V (Edmond et al. 1992). Subsequently, thyristors with blocking voltages of 900 V in both directions have been fabricated on n-type 4H-SiC. The specific on-resistance in these devices is 1.7 mΩcm2 (Palmour et al. 1996). https://www.hslabrasive.com/products/silicon-carbide/green-silicon-carbide.html

Power MOSFETs on SiC have also been the subject of extensive research. Silicon carbide has a significantly higher critical breakdown field than silicon. This allows a power MOSFET on SiC to achieve the same blocking voltage as a similar device on silicon in a much thinner drift region. Unlike thyristors, MOSFETs exhibit a saturating current–voltage characteristic, giving a large safe operating area. Lateral double implanted (D)MOS power transistors have been fabricated on 4H-SiC with blocking voltages of 2.6 kV (Spitz et al. 1997). The schematic and the current (I)–voltage (V) characteristics of this device are shown in Figs. 3 and 4, respectively. The theoretical breakdown voltage for this device is in excess of 10 kV. The increase in blocking voltage for SiC power devices has been dramatic, as shown in Fig. 5. However, they must be accompanied by reductions in specific on-resistance and increases in absolute current rating before these devices will be commercially viable.

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