砷化鎵/砷化鎵以及砷化鎵/鍺晶圓接合介面形態與電性研究

Abstract

近幾年來，三五族材料的研究儼然為半導體工業界發展之重要目標。三五族中的砷化鎵材料具有直接能隙、高頻、抗輻射、耐高溫等眾多優點。不同的半導體材料，如P型或N型之砷化鎵各自具有不盡相同的能隙、電子電洞遷移率、電阻率等材料的物理特性，可用於光電半導體元件、高速電子元件以及太陽能電池等。此篇論文利用晶圓接合技術，在高品質的接合介面之下將這些元件做整合。材料歷經高壓及高溫退火，在試片表面會形成化學鍵進而將材料緊密接合在一起。然而不同材料之間總是存在著熱膨脹係數差異，在高溫之下產生的熱應力不僅會造成試片分離還甚至會使試片破裂。 本實驗選擇P型與N型砷化鎵以及N型鍺與N型砷化鎵作為直接接合研究對象。首先以融合接合法成功地接合晶圓，之後以穿透式電子顯微鏡觀察微結構並作電流電壓特性量測。結果顯示存在於介面的非晶質區域厚度隨著溫度的上升而聚集變薄。電性量測方面則是觀察到典型的二極體特性。

The study of III-V materials has played an important role in semiconductor industry recrntly. GaAs material has varies outstanding advantages such as direct bandgap, high efficiency, radiation resistant, high temperature resistant and so on. Different types of semiconductor materials such as P or N-type gallium arsenide have their own energy gaps, electron and hole mobilities, resistivities and other physical properties of materials. These properties of GaAs material have attracted much interest for optoelectronic semiconductor device, high speed electronics and solar cells. Wafer bonding can provide high quality interface for combination of these materials. During high pressure and high temperature anneal, wafer bonded by producing covalent bond at interface. However, there always exist thermal expansion mismatch between different material, great thermal stress may cause sample debond even crack after annealing. In this study, direct wafer bonding was applied to combine n-GaAs and p-GaAs. First, the samples were successfully bonded by fusing bonding. And then the interface microstructure was investigated by transmission electrical microscopy (TEM) and I-V characteristic was also measured. The amorphous layer between the interface gathered together and the thickness decreases while the temperature increases. From the I-V curve, it’s obvios to see the characteristic of diodes.