Patent ID: 8133577

Claim:
A silicon-nitrogen compound film of a material expressed by a compositional formula Si 3 N x O y H z , where x, y, and z satisfy 10≦(3x+2y)≦12, 3.4≦x≦4.0, 0≦y, and 0<z<2.0, a peak-area ratio of a first area of a first peak appearing near a wave number of 2150 cm −1 in a Fourier-transform infrared absorption spectrum of said material and corresponding to a Si—H stretching vibration to a second area of a second peak appearing near a wave number of 810 cm −1 in the Fourier-transform infrared absorption spectrum and corresponding to a Si—N stretching vibration is smaller than 0.2, and said silicon-nitrogen compound film has a thickness t (in nanometers) and a density d (g/cm 3 ) which satisfy the inequalities, 1.9≦d≦2.5, and −700d+1930≦6t≦−700d+2530.