标题:
SiO2奈米绝缘层对GaAs/Ge异质结构特性之影响Effect of SiO2 Nano-Interlayer to Characteristics of GaAs/Ge Heterostructure
作者:
吴家任, 方劲智, 陈隆建
关键字:
射频磁控溅镀, SiO2奈米绝缘层, 砷化镓, 锗RF Sputter, SiO2 Nano-Interlayer, GaAs, Ge
期刊名称:
《Hans Journal of Nanotechnology》, Vol.4 No.4, 2014-11-28
摘要:
本论文主要探讨SiO2奈米绝缘层对GaAs/Ge异质结构光电特性的影响之研究。本实验主要探讨分为三部分，其一是探讨以射频磁控溅镀技术所成长之砷化镓薄膜磊晶质量及特性分析；其二为透过薄膜分析GaAs/Ge和GaAs/SiO2/Ge两种异质结构，讨论SiO2厚度变化对组件结构的影响；其三则是探讨GaAs/SiO2/Ge异质结构的光电特性。在GaAs/SiO2/Ge的异质结构中，除了大约在53˚的GaAs绕射峰之外，大约在52˚则有另一个强度很强的绕射峰出现，该绕射峰应为氧化镓(Ga2O3)，晶向为(024)，推测应属SiO2的氧(O2)及GaAs的镓(Ga)所反应之生成物。当沉积时间增加时，GaAs的绕射峰强度减弱，Ga2O3的绕射峰强度增强，可能是SiO2引进氧形成Ga2O3，而造成砷的自生点缺陷(native point defect)增加所导致。在照光的情形下，在GaAs的膜层中之砷的自生点缺陷会捕捉光生电子，造成光电流减少，进而影响GaAs/SiO2/Ge异质结构的光特性。
This work investigates the effect of a SiO2 nano-interlayer to optoelectronic characteristics of GaAs/Ge heterostructures. The experimental focuses on three parts: first of all, studying crystal quality of GaAs and GaAs/SiO2 films on Ge substrates prepared by RF magnetron sputtering. Next, it studies the effect of the SiO2 nano-interlayer with different thickness to the properties of the device structure by using the results of the optoelectronic characteristics of the GaAs/Ge and GaAs/ SiO2/Ge heterostructures. Third, we investigate the optoelectronic characteristics of the GaAs/ SiO2/Ge structure In the GaAs/SiO2/Ge heterostructure, except for the diffraction peak of GaAs layer at around 53˚, a strong peak at 52˚ responding to be gallium oxide (Ga2O3) was observed. That is the reaction product of oxygen (O2) and gallium (Ga) from the SiO2 layer. The diffraction peak intensity of GaAs decreases and the diffraction peak intensity of Ga2O3 increases as the deposition time increases. This may contributed to the arsenic native point defect caused by the introduction of oxygen from the SiO2 layer and then to form Ga2O3. Under illumination, the arsenic native point defect in the GaAs layer will capture photo-generated electrons, resulting photocurrent decrease, thereby affecting the optical properties of GaAs/SiO2/Ge heterostructures.