Determination of stress from HR-XRD and Raman for GaN/AlInN/AlN/Sapphire HEMTs

In this study, structural properties of GaN/AlInN/AlN/sapphire high electron mobility transistors (HEMTs), grown by metal organic chemical vapor deposition technique, are investigated. High resolution X-ray diffraction technique (HR-XRD) and Raman mesurements are made to determine stress values and stress type for GaN layers dependent on Al content. It is seen that stress values gained from these two techniques are approximately at the same level. It is noticed that there is tensile stress in all three samples according to Raman shift measurements. Also strain values are calculated by using full width at half maximum (FWHM) values in HR-XRD pattern.