The embodiments of mechanisms for monitoring thermal budget of an etch process of a cyclic deposition/etch (CDE) process to form an epitaxially grown silicon-containing material are descried to enable and to improve process control of the material formation. The monitoring is achieved by measuring the temperature of each processed wafer as a function of process time to calculate the accumulated thermal budget (ATB) of the wafer and to compare the ATB with a reference ATB (or optimal accumulated thermal budget, OATB) to see if the processed wafer is within an acceptable range (or tolerance). The results are used to determine whether to pass the processed wafer or to reject the processed wafer.