Stress and elastic constants of amorphous germanium nitrogen alloys

Thermomechanical properties (stress, thermal expansion coefficient, and elastic modulus) of a-GeNx:H thin films prepared by the rf sputtering technique are reported. Stress measurements are made using a Dektak profilometer to determine the radius of curvature of the film/substrate structure. The majority of the films prepared in this work have compressive stress. A second apparatus based on the deflection of a He-Ne laser beam is used to determine the thermal expansion coefficient and the Young's modulus/(1-Poisson's ratio) by the thermally induced bending method. They depend strongly on the nitrogen concentration.