Near infrared rugate filter fabrication by ion beam assisted deposition of Si_(1−X_)NX films

Abstract

The rugate filter employs a sinusoidal refractive index depth profile to produce high reflection in a narrow band of wavelengths. Fabrication relies on a continuously variable index of refraction in the wavelength regime of interest. The near IR refractive index of amorphous silicon-nitrogen films decreases continuously as the composition varies from pure silicon to stoichiometric silicon nitride (Si(3)N(4)). Ion implantation was found unsuitable as a fabrication method for rugate filters. Homogeneous and inhomogeneous films up to 5 microm in thickness have been produced by simultaneous deposition of electron beam evaporated silicon and of energetic nitrogen particles arising from an ion beam. The relative fluxes of beam and evaporant are found to determine the ratio of nitrogen to silicon in the films and therefore to determine the index. Single-band reflection filters of the rugate design of high peak optical density were fabricated under computer control using a quartz crystal oscillator shielded from the beam to monitor the silicon evaporation and three suppressed Faraday cups to monitor the ion beam current.

Effect of deposition conditions on mechanical properties of low-temperature PECVD silicon nitride films

“…composition of the films can be varied within certain range by adjusting the deposition conditions, including reactant gas mixing ratio and pressure, substrate temperature and plasma power [8][9][10]. The films may also contain hydrogen due to the gas chemistry used for deposition [11].…”

Substrate Temperature Effects on Properties of Silicon Nitride Films Deposited by Ion Beam Assisted Deposition

“…A schematic of the ion beam assisted deposition (IBAD) system was published previously [1]. Electron beam evaporation of 1 pm of Si occurred simultaneously with bombardment of 500 eV nitrogen from a Kaufman ion source.…”

Electrical and Mechanical Characteristics of Room Temperature Deposited Silicon Nitride Using Two Inner Parallel Cylindrical Coils Inductively Coupled Plasma Chemical Vapor Deposition

“…The actual composition of a film can be varied within a certain range by adjusting the deposition conditions, including the reactant gas mixing ratio and pressure, substrate temperature and plasma power. [28][29][30][31] The mechanical properties of a deposited film are significantly influenced by deposition conditions, and can be considerably different from those of the bulk material. 32 Therefore, the mechanical characterization of thin films is essential in gauging the potential structural integrity and performance of MEMS devices and TFT on the flexible substrate.…”