Thin Film Thickness Monitor Research Articles

Voltage readout of a temperature-controlled thin film thickness monitor

A temperature-controlled crystal oscillator installed in a vacuum chamber can be stabilised to within +or-0.05 degrees C at a preset temperature. The frequency shift of the oscillator due to film deposition is detected by a digital mixer implemented by application of AND and NOR gates and is then converted to a voltage by a transistor-diode pump. A linear dependence of voltage readout on film thickness to within 1% of linearity can be obtained.

Feasibility of Thin Film Thickness Monitoring by Holographic Interferometry

This paper describes a potential technique for dynamically monitoring the thickness of a vacuum deposited thin film by holographic interferometry. This technique does not require the use of high quality optical components, the use of optical quality windows in the vacuum chamber wall, or the use of optically smooth film substrates. Experimental data are presented to substantiate the feasibility of the proposed technique. Several potential applications and the inherent advantages of this measurement method are discussed.

A new approach for the thickness monitoring of optical thin films

Accurate measurement in situ of the film thickness during the deposition of thin films for optical applications is achieved by a new photoelectric optical system which measures continuously the reflectance or transmittance of a monitoring plate. The necessity for modulating the light beam is eliminated.

A versatile thin film thickness monitor of high accuracy

A thickness monitor of the oscillating quartz crystal type has been constructed having a sensitivity to a mass of 1ng, corresponding to 0.012 A of aluminium over the working area of 30 mm2. The instrument operates at 4.15 MHz and is accurate to 1% for aluminium films up to 20000 A in thickness. Design considerations are discussed for operation over other thickness ranges. The instrument is simple to construct, small, robust, will give virtually continuous readings and can be used for both metal and dielectric films.