Achieving Sub-0.1 eV Hole Schottky Barrier Height for NiSiGe on SiGe by Aluminum Segregation

作者：Sinha Mantavya^*; Lee Rinus T P; Lohani Anup; Mhaisalkar Subodh; Chor Eng Fong; Yeo Yee Chia

来源：Journal of the Electrochemical Society, 2009, 156(4): H233-H238.

DOI：10.1149/1.3072677

• aluminium
• electrical resistivity
• Ge-Si alloys
• ion implantation
• MOSFET
• nickel alloys
• Schottky barriers
• segregation
• semiconductor epitaxial layers
• semiconductor junctions
• semiconductor materials
• silicon

Nickel germano-silicide (NiSiGe) contact was formed on silicon-germanium (Si(1-x)Ge(x) or SiGe) epilayer with 26% Ge, grown on p-Si (100) substrate. We report the tuning of the effective Schottky barrier height (SBH) of holes at the NiSiGe/SiGe junction to sub-0.1 eV by the introduction of aluminum (Al) using ion implantation and its segregation at the NiSiGe/SiGe interface after germano-silicidation. The effective SBH decreases with increasing concentration of Al at the NiSiGe/SiGe interface. We demonstrate the achievement of one of the lowest reported hole SBHs for NiSiGe on SiGe of 0.068 eV, which is extremely promising for application in p-type metal oxide semiconductor field-effect transistors. The presence of Al does not affect the sheet resistance or the low-resistivity nickel mono-germano-silicide phase of the NiSiGe film. Our results indicate the possibility of an electric dipole at the NiSiGe/SiGe interface, introduced by Al atoms, which is responsible for the SBH modulation. Increase in thickness of nickel used for germano-silicidation increases the effective SBH. The increase in the Al implant dose reduces the effective SBH but degrades the SiGe epilayer by amorphizing it to a greater depth. Thus, a trade-off exists in choosing the Al implant dose and the nickel thickness needed to consume the amorphized SiGe for maximum device performance.

• 出版日期2009
• 单位南阳理工学院