Study On In-situ Measurement System For Phase Transition Temperature Of GeTe Thin Film Materials

Thin film phase change materials are mainly divided into phase change storage materials and phase change energy storage materials,and have a wide range of applications in the field of electronic information,semiconductors,aerospace and new energy.Phase change temperature is a key parameter of thin film phase change materials,and accurate measurement can greatly promote the development of phase change memory,and can provide strong support for the application of phase change energy storage materials.Currently,techniques for determining the phase transition temperature of thin film materials include variable temperature X-ray diffraction and thermal analysis.The former belongs to a range of temperature values,while the latter belongs to lossy measurements.Therefore,there is an urgent need for an accurate and nondestructive method and device to measure the phase transition temperature of thin film materials.In this paper,a phase change temperature measuring instrument for thin film materials was designed and constructed based on optical power method to measure the phase change temperature of thin film materials before and after phase transition,and Ge Te,a typical thin film phase change material,was measured.The content and main results of this study were as follows:1.The hardware part of the phase change temperature measuring instrument for thin film materials was designed,which mainly includes high-temperature heating furnace,optical module,etc.Through Fluent simulation and experiment,the temperature field uniformity of the hightemperature heating furnace cavity was explored.After that,the tightness and vacuum degree of the high-temperature heating furnace were explored,and the PID control ability was explored through the thermal insulation performance,all of which met the experimental requirements.2.According to the measurement principle of optical power method,built an optical power measurement module to measure the phase change temperature of thin film materials.The hardware part of the optical power detector was made,and two structural forms were proposed according to the measurement principle of optical power reflection method,and the second scheme was selected after comparison.The Raman spectroscopy module was designed on the basis of the optical power measurement module,and the parameters of each component were reasonably selected through the Raman scattering principle,and then the structural design drawing of the Raman module was designed,and each component was built according to the design drawing to obtain the Raman measurement module.Solid Works software was used to design the main housing part of the instrument,and let the manufacturer process it and install it on the instrument.Finally,3DSMAX was used to draw the instrument working animation diagram,and the Solid Works software was used to draw and render the overall appearance of the instrument.3.The software part of the phase change temperature measuring instrument of thin film material was designed,and the communication instructions were calculated according to the communication protocol,and then the serial port debugging assistant was used to test the correctness of the communication instructions and the instrument can work normally.Use the VISA function plug-in in Lab VIEW to realize real-time communication with the host computer.VISA was used to write and send the communication password to the host computer in real time,and then VISA was used to read and read the return information of the host computer,and obtain real-time temperature data through related function processing.The DAQ data acquisition system was used to collect the voltage signal of the acquisition card in real time,which was the reflected optical power signal.Using temperature as abscissa and reflected optical power signal as ordinate,drew a temperature-reflected optical power function image in real time.4.The phase transition temperature of Ge Te thin film material with a film thickness of 10 nm was measured by the established instrument,and the phase transition temperature result of Ge Te film material was obtained10 times,and the average value of the measured result was 212.73 °C,the variance was 1.70,and the measurement repeatability was good and met the experimental requirements.Using a calibrated Hall-effector,a range of phase transition temperatures was measured for Ge Te films based on changes in their electrical characteristics before and after the phase transition.After experiments,we concluded that the phase transition temperature of Ge Te film was 215±5°C.The average measurement of the instrument in this paper was 212.73 °C in this range,so the accuracy of the phase change temperature measuring instrument of the thin film material constructed in this paper can be proved.Therefore,this topic has certain research significance and practical application value.