溅射ZnO薄膜钝化GaAs表面性能的研究

为了改善GaAs(110)与自身 氧化物界面由于高表面态密度而引起的费米能级钉扎(pinning)问题 ,提出采用射频磁控溅射技 术在GaAs(110)衬底上沉积一定厚度 ZnO薄膜作为钝化层,并利用光 致发光(PL)光谱和X射线光电子能谱(XPS) 等方法对ZnO薄膜的光学特性及钝化性能进行表征。实验结果表明,经ZnO薄膜钝化后的 GaAs样品,其本征PL峰强度提高112.5%,杂质峰强度下降82.4%。XPS光谱分析表明,Ga和As原子的比值从1.47降低 到0.94,ZnO钝化层能 够抑制Ga和As的氧化物形成。因此,在GaAs表面沉积ZnO薄膜是一种可行的GaAs表面钝化 方法。

Study on surface passivation of GaAs substrates with ZnO films deposited using R F sputtering

Surface passivation of GaAs semiconductor materials has been studied t o improve surface stability.An ultra-thin (~8nm) passivation layer of ZnO on GaAs was prepared by RF deposition method to control the interface trap densities and to prevent the Feimi level pinning.The optical and passivation performance of ZnO film has be en investigated by photoluminescence (PL) and X-ray photoelectron spectroscopy (XPS).An increase in intrinsic PL intensity u p to 112.5% and a decrease in impurity PL intensity down to 82.4% are observed after depositing ZnO films compared with unpassivated GaAs surface.XPS measurement results show that the atomic concentration ratio of Ga/As (originally ~1.47) has been modifie d to a value of ~0.94,indicating an improvement of the surface stoichiometry in GaAs,Ga-O,As-O bonding is found to get effecti vely suppressed in RF deposited ZnO/GaAs interface structures.Passivation enhancement mechanism is also discussed.Research result s indicate that an ultra-thin ZnO film deposited on the GaAs surface is a feasible choice for GaAs surface passivation .