Dp. Looze et al., MODELING AND IDENTIFICATION OF THE LIQUID ENCAPSULATED CZOCHRALSKI GAAS PROCESS FOR CONTROL, Journal of crystal growth, 148(1-2), 1995, pp. 79-95
This paper develops an analytic model of the macroscopic dynamics of t
he liquid encapsulated Czochralski (LEG) GaAs growth process together
with a series of system identification experiments that confirm the va
lidity of the model for control system design and analysis. The model
combines the meniscus dynamics with a low-order model of the thermal d
ynamics of the process. The effective heat transfer coefficients used
in the model are determined from a steady-state finite-element model o
f the process. The identification experiments confirm that the model g
ives accurate predictions of the dominant process dynamics and high fr
equency phase characteristics. Although the model gain at high frequen
cies is less accurate, the error can be identified and accommodated in
the control system design and analysis process.