Abstract :
Temperature is a key parameter of Lithium tantalate (LiTa03) thin film deposition process by metal `organic chemical vapor deposition (MOCVD) because reactor chamber of MOCVD is with properties of a large temperature lag, a big time delay, nonlinear, and a large heat inertia. In this paper, an intelligent temperature control strategy for LiTa03 thin films deposition process is presented and relation between temperature and process is discussed in details. The control strategy is implemented by design of a hybrid temperature control system with Proportional (P), Fuzzy and PID controller. The bumpless switch between two of the three controllers is a key question and has been solved through using fuzzy switch rules. The simulation results show, compared to those of a conventional one, that new temperature control system has a small overshoot, strong robustness, great anti-interference ability and fine temperature tracking ability. The experimental results also attest high resolution of M.2K at stable stage of temperature control is obtained relatively to the maximal temperature of 1373 K.
