Compensation of temperature effects in quartz crystal microbalance measurements

Quartz crystal microbalance (QCM) is a very powerful method for in situ monitoring of thin film growth processes. However, especially at high temperatures, QCM is very sensitive to already minor temperature changes during the measurement. Here, a method for compensating the temperature effects on the QCM is introduced. In this method, the baseline drift during the growth is calculated using a function obtained by fitting the signal measured before and after the growth. The present method is compared with the earlier published reference crystal method where two closely spaced quartz crystals are used, one being protected against film growth and thus serving as a reference crystal for compensating the temperature effects on the measurement crystal. Both methods were tested with TiO2 and Al2O3 atomic layer deposition processes and the temperature effect was successfully compensated. The differences between these methods are discussed.