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用电子束蒸发方法在Si(111)衬底上蒸发了Au/Cr和Au/Ti/Al/Ti两种金属缓冲层,然后在金属缓冲层上用气源分子束外延(GSMBE)生长GaN.两种缓冲层的表面都比较平整和均匀,都是具有Au(111)面择优取向的立方相Au层.在Au/Cr/Si(111)上MBE生长的GaN,生长结束后出现剥离.在Au/Ti/Al/Ti/Si(111)上无AlN缓冲层直接生长GaN,得到的是多晶GaN;先在800℃生长一层AlN缓冲层,然后在710℃生长GaN,得到的是沿GaN(0001)面择优取向的六方相GaN.将Au/Ti/Al/Ti/Si(111)在800℃下退火20min,金属层收缩为网状结构,并且成为多晶,不再具有Au(111)方向择优取向.
The two metal buffer layers Au / Cr and Au / Ti / Al / Ti were evaporated on the Si (111) substrate by electron beam evaporation, and then GaN was grown by gas source molecular beam epitaxy (GSMBE) on the metal buffer layer. The surface of both buffer layers is relatively flat and uniform, and is a cubic Au layer with a preferential orientation of Au (111) plane.MgO grown on Au / Cr / Si (111) GaN is directly grown on the Au / Ti / Al / Ti / Si (111) without AlN buffer layer to obtain polycrystalline GaN; first, an AlN buffer layer is grown at 800 ° C. and then GaN is grown at 710 ° C., The preferred orientation of hexagonal GaN in the GaN (0001) plane is that the Au / Ti / Al / Ti / Si (111) alloy is annealed at 800 ℃ for 20min and the metal layer shrinks to a network structure and becomes polycrystalline with no longer Au 111) orientation preferred orientation.