In this paper, thermally stable Ni germanide using a NiPt(1%) alloy and TiN capping layer is proposed for high-performance Ge MOSFETs. The proposed NiPt(1%) alloy structure exhibits low-temperature germanidation with a wide temperature window for rapid thermal processing. Moreover, sheet resistance is stable and the germanide interface shows less agglomeration despite high-temperature postgermanidation anneal up to 550 °C for 30 min. In addition, the surface of the NiPt(1%) alloy structure is smoother than that of a pure Ni structure both before and after the postgermanidation anneal. Only the NiGe phase and no other phases such as PtxGey and Ni xPt1-xGey can be observed in X-ray diffraction results, but X-ray photoelectron spectroscopy shows that PtGe is formed during the postgermanidation anneal. The larger Pt atomic radius is believed to inhibit the diffusion of Ni into the Si substrate, thereby improving the thermal stability of the NiGe. The higher melting point of PtGe is also believed to improve thermal stability. Therefore, this proposed NiPt(1%) alloy could be promising for high-mobility Ge MOSFET applications.
Bibliographical noteFunding Information:
Manuscript received December 4, 2008. First published June 16, 2009; current version published March 10, 2010. This work was supported in part by the Korea Research Foundation under Grant KRF-2007-521-D00288, and in part by the Korea Science and Engineering Foundation (KOSEF) under Grant 2009-0069103. The review of this paper was arranged by Associate Editor C. Zhou.
All Science Journal Classification (ASJC) codes
- Computer Science Applications
- Electrical and Electronic Engineering