Nickel induced crystallization of /spl alpha/-Si gate electrode at 500/spl deg/C and gate oxide reliability

In this paper, we present a study of the reliability of gate oxide during metal induced crystallization (MIC) of amorphous silicon (/spl alpha/-Si) gate electrode with nickel. MIC is attractive for low thermal budget thin film transistors (S.W. Lee and S.K. Joo, IEEE Electron Device Lett., vol. 17, no. 4, pp. 160-162, 1996) and many papers like Lee et al (ibid., vol. 17, no. 8, pp. 407-409, 1996) have reported using Ni MIC to crystallize and activate dopants in gate a-Si. Since Ni is a fast diffuser (R.M. Burger and R.P. Donovan, 1967) and deep trap (S.M. Sze, 1981) in silicon, it is important to study the effects of Ni MIC on gate oxide and overall capacitor reliability. In order to do that, we measured C-V, I-V and charge to breakdown (QBD) data for capacitors and compared with devices which did not have Ni. Based on these results, we found that Ni did not cause significant degradation of devices.