A simple method for the characterization of thin films during heat treatment

Abstract

 In this paper, we propose a simple method to characterize thin film during heat treatment with a compact structure as a specimen. By detecting the variation of displacements of the structure, thereby, various kinds of information, such as thermomechanical properties, stress relieving, or microstructure variations of thin films during heat treatment, can be characterized from the record of the displacements of the structure. The measurement of displacements can be done directly under an optical microscope with the specimen placed in a heating stage. Based on this method, the specimen is free from substrate, no mechanical constraints imposed on the specimen, and the characterization can display local conditions on a wafer. To set an example, as-deposited polycrystalline silicon films with phosphorous doping on regular high temperature annealing between 550 and 1100 °C are used as a model system to demonstrate the effectiveness of the proposed method for characterizing variations of stress-levels as function of temperature and time during heat treatment.