Fig. 1.
(a) Cross sectional and (b) top view of the fabricated sample. The grey regions show ohmic contact electrodes
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Yanxu Zhu, Weiwei Cao, Yuyu Fan, Ye Deng, Chen Xu. Effects of rapid thermal annealing on ohmic contact of AlGaN/GaN HEMTs[J]. Journal of Semiconductors, 2014, 35(2): 026004. doi: 10.1088/1674-4926/35/2/026004
Y X Zhu, W W Cao, Y Y Fan, Y Deng, C Xu. Effects of rapid thermal annealing on ohmic contact of AlGaN/GaN HEMTs[J]. J. Semicond., 2014, 35(2): 026004. doi: 10.1088/1674-4926/35/2/026004.
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Effects of rapid thermal annealing on ohmic contact of AlGaN/GaN HEMTs
doi: 10.1088/1674-4926/35/2/026004
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Abstract
Ohmic contacts with Ti/Al/Ti/Au source and drain electrodes on AlGaN/GaN high electron mobility transistors (HEMTs) were fabricated and subjected to rapid thermal annealing (RTA) in flowing N2. The wafer was divided into 5 parts and three of them were annealed for 30 s at 700, 750, and 800℃, respectively, the others were annealed at 750℃ for 25 and 40 s. Due to the RTA, a change from Schottky contact to Ohmic contact has been obtained between the electrode layer and the AlGaN/GaN heterojunction layer. We have achieved a low specific contact resistance of 7.41×10-6 Ω·cm2 and contact resistance of 0.54 Ω·mm measured by transmission line mode (TLM), and good surface morphology and edge acuity are also desirable by annealing at 750℃ for 30 s. The experiments also indicate that the performance of ohmic contact is first improved, then it reaches a peak, finally degrading with annealing temperature or annealing time rising.-
Keywords:
- AlGaN/GaN HEMT,
- RTA,
- ohmic contact
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References
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