Furnace control using non-thermal parameters (semiconductor growth)

Conventionally, furnaces are controlled by measuring the temperature and processing the data by, for example, a three-term temperature controller. The authors report successful control of a furnace using non-thermal data taken directly from the heated object. The expansion of a sample tube, in a simulation of a horizontal Bridgmann system for growing GaAs in a quartz tube, provided the integral term of a three-term controller.