Silicon Nitride Films Formed with DC-Magnetron Reactive Sputtering
A dc-magnetron reactive sputtering process, that employs elemental Si and N, has been developed for the deposition of silicon-nitride films.
The substrate temperature during deposition is approximately 50 deg. C
The inlet for Ar is located near the Si target and the one for N2 near the substrate
The substrates are revolving during deposition, in order to obtain controlled and uniform film properties
The film deposition rate is 1 angstrom per revolution, or about 30 angstrom/min.
Several 3-in. dia. round (or otherwise different substrates) can be simultaneously coated.
This film exhibits excellent mechanical strength, high corrosion resistance, low electrical leakage and high dielectric breakdown. Therefore, it has been successfully employed for the encapsulation and passivation of photosensitive amorphous semiconductor films, such as optical memories (1) and electron devices such as thin film OTS switches (2).
The silicon nitride by this process is not perfectly stoichiometric, since Auger analysis has found it nitrogen deficient. Its refractive index by ellipsometry is 1.85-to-l.87, while the refractive index of bulk Si3N4 is 2.00. The very low deposition temperature, which is probably responsible for the incomplete chemical reaction of Si and N2.
KeywordsSilicon Nitride Bevel Gear Silicon Nitride Film Excellent Mechanical Strength Target Voltage
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