Showing papers by "John W. Palmour published in 2007"
TL;DR: In this article, the design and fabrication of 9 kV planar p-IGBTs on 4H-SiC are reported, which exhibits a blocking voltage of 9kV with a leakage current density of 0.1 mA/cm2.
Abstract: SiC IGBTs are suitable for high power, high temperature applications. For the first time, the design and fabrication of 9 kV planar p-IGBTs on 4H-SiC are reported in this paper. A differential on-resistance of ~ 88 m(cm2 at a gate bias of –20 V is achieved at 25°C, and decreases to ~24.8 m(cm2 at 200°C. The device exhibits a blocking voltage of 9 kV with a leakage current density of 0.1 mA/cm2. The hole channel mobility is 6.5 cm2/V-s at room temperature with a threshold voltage of –6.5 V resulting in enhanced conduction capability. Inductive switching tests have shown that IGBTs feature fast switching capability at both room and elevated temperatures.
22 citations
TL;DR: In this paper, high temperature characteristics of 4H-SiC power JFET and DMOSFETs are compared, and a discussion of issues for their high temperature application is presented.
Abstract: High temperature characteristics of 4H-SiC power JFETs and DMOSFETs are presented in this paper. Both devices are based on pn junctions in 4H-SiC, and are capable of 300oC operation. The 4H-SiC JFET showed very predictable, well understood temperature dependent characteristics, because the current conduction depends on the drift of electrons in the bulk region, which is not restricted by traps in the MOS interface or at the pn junctions. On the other hand, in a 4H-SiC DMOSFET, electrons must flow through the MOS inversion layer with a very high interface state density. At high temperatures, the transconductance of the device improves and threshold voltage shifts negative because less electrons are trapped in the interface states, resulting in a much lower MOS channel resistance. This cancels out the increase in drift layer resistance, and as a result, a temperature insensitive on-resistance can be demonstrated. The performance of the two devices are compared, and a discussion of issues for their high temperature application is presented.
16 citations
TL;DR: The development of 4H-SiC PiN diodes capable of blocking to greater than 10 kV while having current ratings of 20 A at 100 A/cm2 is continuing in earnest as discussed by the authors.
Abstract: The development of 4H-SiC PiN diodes capable of blocking to greater than 10 kV while having current ratings of 20 A at 100 A/cm2 is continuing in earnest. VF instability of these diodes continues to be a roadblock, but progress is being made, and a 20 A/10 kV 4H-SiC PiN diode wafer with an overall device yield of 40% has been fabricated. The latest device characteristics are discussed, along with details of approaches in improving the reverse recovery characteristics of these diodes to satisfy the requirements needed for implementation into high voltage inverter modules capable of switching at up to 20 kHz.
12 citations
TL;DR: In this paper, the authors measured the forward currentvoltage and non-equilibrium carrier lifetime of 4H-SiC pin diodes (10-kV rated, 100 μm base width).
Abstract: Forward current-voltage (I-V) characteristics and non-equilibrium carrier lifetime, τ were measured in 4H-SiC pin diodes (10-kV rated, 100 μm base width). The τ value was found to be 3.7 μs at room temperature by measurements of open circuit voltage decay. To the best of the authors' knowledge, the above lifetime value is the highest reported for 4H-SiC. The forward voltage drops were measured to be 3.44 V at current density of 100 A/cm2 and 5.45 V at 1000 A/cm2 showing a very deep modulation of the blocking base by injected carriers. Diodes operated well at elevated temperatures up to 400oC. No essential forward degradation was detected after 300- A×min current stress at 400oC.
2 citations