Physical‐Electrical Properties of Silicon Nitride Deposited by PECVD on III–V Semiconductors

Silicon nitride films have been produced from and by reactive plasma deposition. This paper describes the effect of deposition parameters, i.e. , substrate temperature , RF power (20–150W), and gas ratio (1–19), on various film properties deposited on III–V semiconductor substrate. A parameter working range has been identified suitable for III–V technology, that is , RF power , and ammonia/silane ratio . Under these conditions films have been made with a Si/N ratio of 0.7–1 and a refractive index of 1.9–2. Electrical resistivity greater than 10 12 Ω cm at a field of 2 MV/cm, breakdown strength of 3–9 MV/cm at a current of 1 μA, and a dielectric constant of 7 were observed. The density of interface states for the silicon system was evaluated at . Si‒H and N‒H bonds per unit area, evaluated by IR measurements, were very low, especially after an annealing procedure. Excellent step coverage and good adhesion were obtained for ridge and mushroom structure lasers. Finally, a RF power of 50W gives silicon nitride layers particularly stable with temperatures.