Reverse bias stress test of GaN HEMTs for high-voltage switching applications

Resolving failure origins of AlGaN/GaN light emitting diodes (LED) has received intensive study recently. In this study, formation of GaCO3 caused by carbon contamination may result in deformation of the electrode near the surface and degrade the device. The electrochemical reactions may cause device damages. Degradation in electrical properties is observed in I-V characteristics. Forward-bias and reverse-bias EL images are used to trace the damaged areas. Furthermore, focus ion beam (FIB), scanning electron microscope (SEM), energy dispersive X-ray diffraction (EDX) are applied to examine the damaged areas. Results indicate that formation of GaCO3 may deform the electrode, generate the reverse-bias EL and cause the degradation.

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Investigation on Electrical Degradation of High Voltage nLDMOS After High Temperature Reverse Bias Stress

IEEE Transactions on Device and Materials Reliability ◽

10.1109/tdmr.2014.2308916 ◽

2014 ◽

Vol 14 (2) ◽

pp. 651-656 ◽

Cited By ~ 3

Keyword(s):

High Temperature ◽

High Voltage ◽

Reverse Bias ◽

Bias Stress ◽

Electrical Degradation

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Reliability of High Voltage 4H-SiC MOSFET Devices

MRS Proceedings ◽

10.1557/proc-0911-b13-01 ◽

2006 ◽

Vol 911 ◽

Cited By ~ 5

Author(s):

Sumi Krishnaswami ◽

Sei-Hyung Ryu ◽

Bradley Heath ◽

Anant Agarwal ◽

John Palmour ◽

...

Keyword(s):

High Temperature ◽

Threshold Voltage ◽

Reverse Bias ◽

Stress Test ◽

Drain Current ◽

Gate Oxide ◽

Bias Stress ◽

Device Stability ◽

Device Reliability

AbstractThe commercialization of 4H-SiC MOSFETs will greatly depend on the reliability of gate oxide. Long-term gate oxide reliability and device stability of 1200 V 4H-SiC MOSFETs are being studied, both under the on- and off-states. Device reliability is studied by stressing the device under three conditions: (a) Gate stress - a constant gate voltage of +15 V is applied to the gate at a temperature of 175°C. The forward I-V characteristics and threshold voltage are monitored for device stability, (b) Forward current stress – devices are stressed under a constant drain current of Id = 4 A and Vg = 20 V. The devices were allowed to self-heat to a temperature of Tsink = 125°C and the I-V curves are monitored with time, and (c) High temperature reverse bias testing at 1200 V and 175°C to study the reliability of the devices in the off-state. Our very first measurements on (a) and (b) show very little variation between the pre-stress and post-stress I-V characteristics and threshold voltage up to 1000 hrs of operation at 175°C indicating excellent stability of the MOSFETs in the on-state. In addition, high temperature reverse bias stress test looks very promising with the devices showing very little variation in the reverse leakage current with time.

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