摘要
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.
Au/Cr and Au/Ti/A1/Ti metal buffer layers were respectively deposited on Si（111） substrate by electron beam evaporation,and GaN was grown on these metal films by gas source molecular beam epitaxy（GSMBE）. The as-deposited metal films have a flat and featureless surface and show diffraction peaks of （111）-oriented cubic Au. The GaN grown on Au/Cr/Si（111） breaks off when cooled to room temperature. GaN grown on Au/Ti/A1/Ti/Si（111 ） without an A1N buffer layer was amorphous. By adding an A1N buffer, GaN grown on A1N/Au/Ti/A1/Ti/Si（111） shows diffraction peaks of （0001）-oriented hexagonal GaN. After annealing at 800℃ for 20min,the metal films of Au/Ti/A1/Ti/Si（111） became amorphous and convert to a porous metal network.
