Improved Ohmic Performance by the Metallic Bilayer Contact Stack of Oxygen-Incorporated La/Ultrathin TiSi x on n-Si

This paper proposes a La/ultrathin TiSi x metallic bilayer contact (MBC) on moderately doped n + -Si, which can simultaneously reduce contact resistivity ( $\rho _{c}$ ) and at the same time improve the contact thermal endurance. In such an MBC, the top La defines the work function (WF), whereas the ultrathin (~1 nm) TiSi x (WF-transparent) interlayer acts as a Si-diffusion barrier and improves the thermal endurance of the whole contact. Moreover, incorporation of oxygen (O) into MBC further improves the contact performance. On n + -Si with a donor concentration of $\textsf {1} \times \textsf {10}^{\textsf {19}}$ cm −3 , an O-incorporated MBC can achieve an $18.3\times $ and $2.2\times $ reduction in $\rho _{c}$ as compared with Ti/n + -Si and La/n + -Si references, respectively.