Electrical and Microstructural Characterization of Cu-Germanide Contacts Formed on p-Type Ge Substrate

Monday, 6 October 2014: 17:35
Expo Center, 1st Floor, Universal 8 (Moon Palace Resort)
Y. R. Lim, Y. J. Lee, M. S. Kang, C. H. Leem, I. Jyothi, K. H. Shim, and C. J. Choi (Chonbuk National University)
We have investigated the electrical and microstructural properties of Cu-germanide formed on p-type Ge substrate as a function of rapid thermal annealing (RTA) temperature. As increasing RTA temperatures, Cu films reacted with Ge and formed Cu-germanides. The Cu3Ge phase appears to be the dominant phase along with Cu5Ge2 phase at annealing temperatures of 500 and 600 °C. The sheet resistance and specific contact resistivity were investigated as a function of germanide formation temperature. A minimum specific contact resistivity value of 6.19´10-6 Ωcm2 is obtained after annealing at 400 °C associated with the formation of stoichiometric Cu3Ge.  The sheet resistance and specific contact resistivity increased after rapid thermal at temperatures >500 °C indicated the degradation of the contact properties and could be associated with the formation of copper rich Cu5Ge2phase and the loss of structural integrity with increasing annealing temperature.