A method for optical in-situ process control of the manufacturing process of a semiconductor device

The invention relates to a method for optical in-situ process control of the production process of an absorber layer of the type ABC a) providing an RTP furnace having a reaction chamber, comprising at least one radiant heater and at least one radiation detector, the radiation detector has a detection region in the wavelength range of 1000 nm to 2500 nm and the radiation detector is disposed so that its optical field of view no direct radiation from the radiant heater detected; b) providing a substrate coated with the components A and B as well as the carrier substrate a defined amount of the component C or a C-containing compound in the reaction chamber of the RTP furnace; and c) heating the reaction vessel in the reaction chamber of the RTP furnace through the at least one radiant heater, thereby simultaneously detecting a light reflected on the resulting absorber layer heat radiation through the at least one radiation detector.