GaN films on sapphire substrates are obtained using the metal-organic chemical vapor deposition growth technique.We present two methods to reduce the GaN wafer bowing caused by the mismatch of the thermal expansion co...GaN films on sapphire substrates are obtained using the metal-organic chemical vapor deposition growth technique.We present two methods to reduce the GaN wafer bowing caused by the mismatch of the thermal expansion coefficients(TECs)between the film and the substrate.The first method is to use coating materials on the back side of the substrate whose TECs are smaller than that of the GaN films.The second is to cut grooves on the back side of the sapphire substrate and filling the grooves with appropriate materials(e.g.,tungsten,silicon nitride).For each method,we minimize wafer bowing and even reduce it to zero.Moreover,the two methods can reduce stress concentration and suppress the propagation of cracks in the GaN/sapphire structure.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 10872003,10932001 and 61006035the Foundation for the Author of National Excellent Doctoral Dissertation of China under Grant No 2007B2+1 种基金the Research Fund for the New Teacher Program of the State Education Ministry of China under Grant No 200800011011the Scientific Research Foundation for the Returned Overseas Chinese Scholars State Education Ministry of China,and China Postdoctoral Science Foundation under Grant No 20090460168.
文摘GaN films on sapphire substrates are obtained using the metal-organic chemical vapor deposition growth technique.We present two methods to reduce the GaN wafer bowing caused by the mismatch of the thermal expansion coefficients(TECs)between the film and the substrate.The first method is to use coating materials on the back side of the substrate whose TECs are smaller than that of the GaN films.The second is to cut grooves on the back side of the sapphire substrate and filling the grooves with appropriate materials(e.g.,tungsten,silicon nitride).For each method,we minimize wafer bowing and even reduce it to zero.Moreover,the two methods can reduce stress concentration and suppress the propagation of cracks in the GaN/sapphire structure.
