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采用AlN缓冲层技术在蓝宝石衬底上通过MOCVD方法成功制备出0.5μm的Si掺杂Al0.5Ga0.5N外延薄膜,并对其电学、光学与结构特性进行了研究。Hall测量表明,在室温下n型Al0.5Ga0.5N中的载流子浓度和迁移率分别为1.2×1019cm-3和12cm2/V.s。载流子浓度随Si掺杂量的增加而增大。利用XRD和Raman等测量方法研究了Si掺杂Al0.5Ga0.5N薄膜晶格常数c和Raman散射谱随SiH4流量的变化。随着SiH4流量的增大,Al0.5Ga0.5N薄膜的晶格常数c变小同时E2声子峰发生红移,这表明掺Si后Al0.5Ga0.5N薄膜中的压应力得到了一定程度的弛豫。
A 0.5μm Si-doped Al0.5Ga0.5N epitaxial film was successfully fabricated on a sapphire substrate by MOCVD using AlN buffer layer technology. The electrical, optical and structural properties of the films were also studied. Hall measurements show that the carrier concentration and mobility in n-type Al 0.5 Ga 0.5 N are 1.2 × 10 19 cm -3 and 12 cm 2 / V.s, respectively, at room temperature. The carrier concentration increases with the increase of Si doping. The lattice constant c and Raman scattering spectra of Si-doped Al0.5Ga0.5N thin films with SiH4 flow rate were investigated by XRD and Raman measurements. With the increase of SiH4 flow rate, the lattice constant c of Al0.5Ga0.5N thin film decreases and the E2 phonon peak shifts red, which indicates that the compressive stress in the Al0.5Ga0.5N thin film is increased to some extent Relaxation.