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通过改变高温AlN形核层生长时提前通入TMAl的时间,分别在Si(111)衬底上生长了4个1μm厚的GaN样品,并对每个样品的GaN外延材料进行了分析研究。通过显微镜观察发现,Al的沉积时间为12 s时,GaN材料表面光亮,基本没有裂纹。另外通过喇曼谱和光荧光谱(PL)测试得出,随着生长初期Al沉积时间的增加(8～15 s),GaN外延层的水平应力逐渐减小(由1.28 GPa减小到0.67 GPa),Al的沉积时间为12 s时GaN外延材料的应力较小。同时,GaN材料(002)和(102)晶面的X射线衍射摇摆曲线表明,Al的沉积时间为12 s时GaN外延材料的晶体质量最好。
By changing the time of advance of TMAl during the growth of high temperature AlN nucleation layer, four 1μm thick GaN samples were grown on Si (111) substrate, and the GaN epitaxial material of each sample was analyzed. The microscopic observation shows that when the Al deposition time is 12 s, the surface of the GaN material is bright with almost no cracks. In addition, the Raman spectra and PL spectra show that the horizontal stress of GaN epitaxial layer decreases gradually from 1.28 GPa to 0.67 GPa with the increase of Al deposition time (8-15 s) , The deposition time of Al is 12 s, the stress of GaN epitaxial material is smaller. Meanwhile, the X-ray diffraction rocking curves of the (002) and (102) crystal planes of GaN show that the crystal quality of the GaN epitaxial material is the best when the Al deposition time is 12 s.