Optimizing Cobalt Silicide Interfaces With Carbon PAI: Enhanced Thermal Stability and Reduced Specific Contact Resistivity for DRAM Applications

For its future application in 4F<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> dynamic random access memory (DRAM) with vertical transistor architecture, it is critical to enhance the thermal stability as well as to reduce specific contact resistivity (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\rho _{\text {c}}$ </tex-math></inline-formula>) of CoSi<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>/n<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup>-Si contacts. In this work, the carbon preamorphization implantation (PAI) method to simultaneously decrease the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\rho _{\text {c}}$ </tex-math></inline-formula> and improve thermal stability of CoSi<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> is proposed. The electrical property and morphology of the CoSi<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>/n<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup>-Si contact with and without carbon PAI are systematically investigated. Compared to the reference without carbon, the samples with carbon PAI achieve a 68.2% reduction in <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\rho _{\text {c}}$ </tex-math></inline-formula>, as well as significantly lowered sheet resistance (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${R}_{\text {s}}$ </tex-math></inline-formula>) of CoSi<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> after high-temperature annealing at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$950~^{\circ }$ </tex-math></inline-formula> C/30 s <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$+ 750~^{\circ }$ </tex-math></inline-formula> C/30 min. These findings manifest the critical role of carbon in reducing <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\rho _{\text {c}}$ </tex-math></inline-formula> and enhancing the thermal stability of CoSi<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>, providing valuable insights for advancing DRAM technology.