Condition Necessary for a Linear Relationship Between Ion Current Nd Deposition Rate

摘要

A mathematical study of the ionization rate monitor is made to establish the relationship between the ion current in the rate sensor and the rate of deposition of film upon a substrate. This relationship is necessary for designing a thickness monitor which indicates the time integral of deposition rate. If the deposition rate were proportional to the ion current, then the ion current could be directly integrated electronically to indicate the thickness of the deposited film; but if the deposition rate were a non-linear function of the ion current, then the ion current would have to be fed into a circuti that would perform certain operations upon the ion current that would give an output, proportional to deposition rate, which could then be integrated electronically. The mathematical condition necessary for the ion current in the evaporation rate monitor to be proportional to the deposition rate is found and shown to be satisfied. The limitations of this analysis are discussed. (Author)