Long-term stability of ICPCVD a-Si under prolonged heat treatment

Inductively coupled plasma enhanced chemical vapor deposited (ICPCVD) a-Si is used as a structural material in many microelectromechanical systems (MEMS). For a-Si to function as a sound structural component, the material must display long term mechanical stability. This paper evaluates the Young's modulus, hardness, and residual stress of a-Si under prolonged heat treatment. It is found that Young's modulus and hardness are not impacted by heat treatment, while the residual stress becomes more tensile with increased annealing time. Increased tensile stress is a result of hydrogen offgassing which can lead to improved film stability [1].