Ohmic contacts to AlGaN/GaN HEMTs: A Comparison of Two Different Ti/Al Metaletal Ratios
Ohmic contacts formed with two different metal stacks; by varying the Ti/Al thickness ratio were rapid thermal annealed in the temperature range 740–820 °C for 30 s in N2 ambience. The ohmic contact formed with Ti/Al metal thickness ratio 1/5 showed lower Rc values and smoother surface morphology compared to the contact with Ti/Al metal thickness ratio 1/1.5. The difference in behavior for both the contacts was corroborated with the outcome of different metallurgical reactions as observed by X-ray diffraction (XRD) and Energy dispersive X-ray analysis (EDX).
KeywordsOhmic contact Ti/Al metal thickness ratio AlGaN/GaN HEMT XRD
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Authors are thankful to Mr Anand for carrying out EDX analysis. Authors are grateful to Dr. R Muralidharan, Director, Solid State Physics Laboratory, Delhi for his guidance and permission to publish this work.
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