Improved Ohmic Performance by the Metallic Bilayer Contact Stack of Oxygen-Incorporated La/Ultrathin TiSi<italic> <sub>x</sub> </italic> 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 (ρ _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 1 × 10 ¹⁹ cm ^-3 , an O-incorporated MBC can achieve an 18.3× and 2.2× reduction in ρ _c as compared with Ti/n ⁺ -Si and La/n ⁺ -Si references, respectively.