Improved SOI FinFETs Performance With Low-Temperature Deuterium Annealing
Ja-Yun Ku, Ji‐Man Yu, Dong-Hyun Wang, Daehan Jung, Joon‐Kyu Han, Yang‐Kyu Choi, Jun-Young Park
Abstract
Low-temperature deuterium annealing (LTDA) was applied to a silicon-on-insulator (SOI) n-channel FinFET to improve device performance and reliability. LTDA at 300 °C, which is roughly 100 °C lower than a conventional forming gas annealing (FGA) process with hydrogen, is attractive to reduce the thermal budget. To confirm improved performance, the ON-state current ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I}_{\text {on}}{)}$ </tex-math></inline-formula> , OFF-state current ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I}_{\text {off}}{)}$ </tex-math></inline-formula> , subthreshold swing (SS), trans-conductance ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${g}_{m}{)}$ </tex-math></inline-formula> , and gate leakage current ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I}_{\text {G}}{)}$ </tex-math></inline-formula> were evaluated. Thereafter, the parasitic 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">${R}_{\text {poly,sheet}}$ </tex-math></inline-formula> ) of gate was characterized and compared between before and after LTDA. The decreased <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${R}_{\text {poly,sheet}}$ </tex-math></inline-formula> induced by LTDA is attractive for reducing <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RC</i> delay. In a reliability point of view, damaged device characteristics by intentional hot-carrier injection (HCI) were recovered by LTDA. In addition to electrical analyses of LTDA effects, deuterium to form the Si–D bonds at the Si channel interface was physically mapped along the perpendicular direction to a FinFET by using time-of-flight secondary-ion mass spectrometry (ToF-SIMS).