Automatización del control térmico de un sistema de evaporación de películas delgadas utilizando LabView

In this paper the automation of an evaporation system used, to grow semiconductor thin films by Close Spaced Vapor Transport combined with Free Evaporation (CSVT-FE) method using LabView, is presented. The system uses three graphite blocks as heaters in order to evaporate the source materials. The electrical current is applied to every graphite block by means of a programmable power supply. The temperatures of the graphite blocks were monitored using type-K thermocouples. The software was developed using Labview 7.0, as a virtual instrumentation language of the programming focused on the automation, which allows manipulating the current of each of the power supplies applied to the graphite. Thus, during a run-time the temperature and the electrical current applied to each heater are obtained. The developed software allows to program ramps and isotherms of temperature with time; in addition, during the run-time, a plot of the temperature with time for each graphite block is displayed; meanwhile the electrical current and temperature are stored in a data file. This technique was applied for the growth of CdxZn1-xTe semiconductor films; moreover, characterization of these films by Energy Dispersive Analysis X-ray (EDAX) and optical transmission techniques was made.