ScAlN缓冲层厚度对Si(100)衬底上GaN外延层的影响

采用脉冲直流磁控溅射方法在Si(100)衬底上制备了ScAlN薄膜。以溅射的ScAlN作为缓冲层,在Si(100)衬底上用金属有机化学气相沉积(MOCVD)技术外延了GaN薄膜。使用高分辨X射线衍射、原子力显微镜和拉曼光谱研究了ScAlN缓冲层的厚度对ScAlN缓冲层和GaN外延层的影响。研究结果表明,ScAlN缓冲层的厚度是影响GaN薄膜晶体质量的重要因素。随着ScAlN厚度的增加,ScAlN的(002)面X射线衍射摇摆曲线半高宽持续减小,GaN的(002)面X射线衍射摇摆曲线半高宽先减小后增大。当ScAlN缓冲层厚度为500nm时,得到的GaN晶体质量最好,其中GaN(002)面的X射线衍射摇摆曲线半高宽为0.38°,由拉曼光谱计算得到的张应力为398.38MPa。

Effect of ScAlN Buffer Layer Thickness on GaN Epitaxial Layer on Si(100) Substrate

ScAlN thin films were first prepared on Si (100) substrate by pulsed DC magnetron sputtering. Then, GaN thin films were epitaxial grown on Si (100) substrate with metal-organic chemical vapor deposition (MOCVD) by using ScAlN as the buffer layer. The influence of the thickness of ScAlN buffer layer on ScAlN buffer layer and GaN epitaxial layer is investigated by high resolution X-ray diffraction, atomic force microscopy (AFM) and Raman spectroscopy. The results show that the thickness of ScAlN buffer layer is an important factor affecting the crystal quality of GaN thin films. With the increase of ScAlN thickness, the full width at half maximum (FWHM) of ScAlN (002) X-ray diffraction rocking curve continues to decrease, and the FWHM of GaN (002) X-ray diffraction rocking curve first decreases and then increases. When the thickness of ScAlN buffer layer is 500nm, the crystal quality of GaN is the best, the FWHM of GaN (002) X-ray diffraction rocking curve is 0.38°, and the tensile stress calculated by Raman spectrum is 398.38MPa.