AVS 53rd International Symposium
    Electronic Materials and Processing Thursday Sessions
       Session EM-ThP

Paper EM-ThP13
Reliability Performance and Electrical Comparison of TiB@sub 2@ ,CrB@sub 2@ and W@sub 2@B@sub 5@ Based Ohmic Contacts on n-GaN

Thursday, November 16, 2006, 5:30 pm, Room 3rd Floor Lobby

Session: Electronic Materials and Processing Poster Session
Presenter: R Khanna, University of Florida
Authors: R Khanna, University of Florida
S.J. Pearton, University of Florida
F. Ren, University of Florida
I.I. Kravchenko, University of Florida
Correspondent: Click to Email
Three different metal borides (TiB@sub 2@, CrB@sub 2@ and W@sub 2@B@sub 5@) were examined for use in Ti/Al/boride/Ti/Au Ohmic contacts on n-type GaN and the reliability compared to the more usual Ti/Al/Ni/Au metal scheme. The minimum specific contact resistance obtained was in the range 10@super -5@ @ohm@.cm@super 2@ with CrB@sub 2@ and W@sub 2@B@sub 5@ and approximately an order of magnitude lower with TiB@sub 2@. In all cases, the minimum contact resistance is achieved after annealing in the range 700-900°C. The main current transport mechanism in the contacts after this annealing is tunneling as determined by the absence of any significant measurement temperature dependence to the contact resistance. The TiB@sub 2@ and CrB@sub 2@ contacts retain smooth morphology even after annealing at 1000° C. Auger Electron Spectrosopy depth profiling indicated that formation of an interfacial TiN@sub X@ layer is likely responsible for the Ohmic nature of the contact after annealing. All three boride-based contacts show lower contact resistance than Ti/Al/Ni/Au after extended aging at 350°C.