Type-2 Fuzzy User Interface for Artificial Neural Network based Decision Support System for Course Selection

An HSG-Si layer is formed on a wafer under a uniform temperature condition. An apparatus for forming the HSG-Si layer includes a housing forming a process chamber, a first heater on which the wafer is positioned fixed in place at the bottom of the process chamber, a second heater at the top of the process chamber, and a thermal insulator which prevents the heat generated by the first heater from being transferred to the outside of the process chamber. A temperature control system regulates the temperature of the heaters. A method of forming the HSG layer includes steps of placing the wafer on the first heater, using the heaters to remove moisture from the wafer, injecting a source gas of the HSG-Si toward the upper surface of the wafer to form amorphous silicon on the wafer, and annealing the wafer for a predetermined period of time to transform the amorphous silicon into an HSG-Si layer. During the steps of forming the HSG-Si layer, the temperatures of the first and second heaters are regulated to maintain the surface temperature of the wafer constant.