论文信息 - Optimisation of the Ti/Al/Ni/Au ohmic contact on AlGaN/GaN FET structures

Optimisation of the Ti/Al/Ni/Au ohmic contact on AlGaN/GaN FET structures

Abstract We present a systematic approach to reduce the resistance of ohmic contacts on AlGaN/GaN FET structures. We have optimised the Ti/Al/Ni/Au contact with respect to the metal composition and annealing conditions. Our optimised contact has a very low contact resistance of 0.2 Ω mm (7.3×10 −7 Ω cm 2 ), a good reproducibility and an excellent line definition, making this contact very suitable for use in AlGaN/GaN FETs with short gate-source distances. This contact resistance on FET material is among the best values reported. The approach presented here can be applied to other metal schemes like Ti/Al/Pt/Au or Ti/Al/Ti/Au.

[1] M. Shur,et al. HALL MEASUREMENTS AND CONTACT RESISTANCE IN DOPED GAN/ALGAN HETEROSTRUCTURES , 1996 .

[2] P. Kozodoy,et al. Bias dependent microwave performance of AlGaN/GaN MODFET's up to 100 V , 1997, IEEE Electron Device Letters.

[3] J. Zolper,et al. Nonalloyed Ti/Al Ohmic contacts to n‐type GaN using high‐temperature premetallization anneal , 1996 .

[4] H. Morkoç,et al. Very low resistance multilayer Ohmic contact to n‐GaN , 1996 .

[5] M.A. Khan,et al. 0.12-μm gate III-V nitride HFET's with high contact resistances , 1997, IEEE Electron Device Letters.

[6] Y. L. Chen,et al. High performance AlGaN/GaN HEMT with improved ohmic contacts , 1998 .