A method for the continuous measurement of thickness and deposition rate of conducting films during a vacuum evaporation

An electronic method for the measurement of thickness and deposition rate of conducting films during a vacuum evaporation is described. Operational amplifiers are employed to monitor the change in resistance of a deposited layer and their outputs used to servo control the deposition rate and automatically cut off the vapour stream when the deposit has reached a predetermined thickness. The equipment allows close control of the deposition rate and thickness, thereby increasing the uniformity of deposited layers during successive evaporations.