L.B. Rowland

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Silicon Carbide (4H-SiC), asymmetrical gate turn-off thyristors (GTO's) were fabricated and tested with respect to forward voltage drop (V/sub F/), forward blocking voltage, and turn-off characteristics. Devices were tested from room temperature to 350/spl deg/C in the dc mode. Forward blocking voltages ranged from 600-800 V at room temperature for the(More)
AlGaN/GaN high electron mobility transistors (HEMTs) have demonstrated great potential for microwave power transmitter applications as required by phased array radar and wireless base stations. In this paper, we report on state-of-the-art power density generated from large gate periphery AlGaN/GaN HEMTs. At 2.8 GHz, 7 W/mm gate periphery (14.7 W total) was(More)
We report for the first time 10 GHz power performance of SiC MESFETs fabricated on Northrop Grumman high resistivity 4H-SiC substrates. We have obtained a power output of 6 Watts at 10 GHz using a 1.92 mm periphery MESFET with 0.5 /spl mu/m gate length. The associated gain, drain efficiency, and power added efficiency were 5.1 dB, 50%, and 34.6%(More)
Silicon Carbide (4H-SiC), power UMOSFETs were fabricated and characterized from room temperature to 200/spl deg/C. The devices had a 12-/spl mu/m thick lightly doped n-type drift layer, and a nominal channel length of 4 /spl mu/m. When tested under Fluorinert/sup TM/ at room temperature, blocking voltages ranged from 1.0 kV to 1.2 kV. Effective channel(More)
This work reports on Fowler-Nordheim (F-N) injection studies on n-type 6H-SiC and 4H-SiC MOS systems under positive gate bias from 25 to 325/spl deg/C. At a given temperature and electric field, the current density in the 4H-SiC MOS system is about five times higher than that in 6H-SiC due to the smaller effective barrier height for the 4H-SiC MOS system as(More)
In this paper, self-heating effects are more pronounced in high-power AlGaN/GaN HEMTs, which have demonstrated more than 10 times power densities. The elevated junction temperature caused by the self-heating effects degrade the available drain current and subsequently the output power due to reduced electron saturation velocity and low-field mobility.
While the advantages of SiC power MOSFETs (both UMOS and DMOS type structures) are known, processing issues have prevented these devices from reaching commercial systems. We evaluate the 4H-SiC DMOS (DIMOS) structure and the 4H-SiC UMOS structure using experimental results. We have achieved 1.1 kV SiC UMOS devices and 900 V SiC DMOS devices, which represent(More)
Silicon Carbide (SiC) is an emerging semiconductor material which has been widely predicted to be superior to both Si and GaAs in the areas of microwave power devices, power electronic switching devices, high temperature analog and digital electronics, non-volatile memories and UV sensors. This paper presents an overview of SiC electronic properties,(More)
For the first time, high gain 4H-SiC static induction transistors (SITs) have been fabricated using a sub-micron source airbridging technique. These devices exhibit record 15 dB small signal gain at 3 GHz. This represents the highest gain yet reported for a SIT structure in any semiconductor.