Low stress atomic layer deposited alumina for nano electro mechanical systems

A new fabrication process, test structures, and measurements of material properties are presented for atomic layer deposited (ALD) alumina (Al/sub 2/O/sub 3/) nanoelectromechanical systems (NEMS). ALD Al/sub 2/O/sub 3/ has similar electrical and mechanical properties to silicon nitride (Si/sub x/N/sub y/) and can be used in many of the same applications. Yet ALD Al/sub 2/O/sub 3/ is an advantageous material to use over Si/sub x/N/sub y/ due to the low deposition temperature, which allows for integration with CMOS processing. Also, ALD Al/sub 2/O/sub 3/ has a high chemical resistance to Si etchants. In this work the stress in ALD Al/sub 2/O/sub 3/ is measured to be /spl sigma/=401/spl plusmn/32 MPa and /spl sigma/=445/spl plusmn/66 MPa for 100 nm and 50 nm thick Al/sub 2/O/sub 3/ films, respectively. The measured Young's modulus is in the range of 110-120 GPa.