FRACTURE STRENGTH AND BIAXIAL MODULUS MEASUREMENT OF PLASMA SILICON-NITRIDE FILMS

The biaxial modulus, ultimate tensile strength and residual stress of silicon nitride films are investigated using the bulge test technique. These films are deposited by plasma-enhanced chemical vapor deposition on gallium arsenide substrates. Biaxial moduli of films 1-mu-m thick with two different chemical compositions were measured. The nitrogen-rich composition has a biaxial modulus of 160 GPa and an ultimate tensile strength of 420 MPa, while the silicon-rich composition has a biaxial modulus of 110 GPa and an ultimate tensile strength of 390 MPa. A comparison with previously reported mechanical properties for silicon nitride films is discussed.