矽鍺磊晶薄膜、氧化鋁表面鈍化與非晶矽材料之光性分析

Abstract

在本篇論文中，將以光性為主的方式，分析半導體材料的特性。為了有效降低成本並提高各半導體元件的操作性質，在各種薄膜層被成長後，以非破壞性的光致發光技術，檢測材料暨界面的品質，已經成為重要的一環。因此本論文將利用此技術分別探討矽鍺磊晶薄膜、氧化鋁鈍化矽與非晶矽薄膜材料。 在第二章中，將利用光致發光、電子顯微鏡、等光電技術去分析不同反應氣體(氫氣及氮氣)，造成矽鍺薄膜成長速率、缺陷以及鍺的含量多寡等差異。接著第三章中，將介紹將鋁以熱氧化的方式去形成氧化鋁並與原子薄膜層積的氧化鋁比較。同時，也將介紹以原子薄膜層積方式形成的氧化鋁及氧化鈦的雙層結構構成有效鈍化層及抗反射層的方法，並且分別去探討各鈍化層對光致發光強度以及少數載子生命週期的影響。最後，第四章將分析兩種不同非晶矽薄膜的差異，探討在成長時，是否加入氫氣對非晶矽薄膜的光性影響。其中將利用吸收係數比較半導體材料的能階、缺陷數。以光致發光以及少數載子生命週期比較鈍化層界面的優劣，並以傅立葉轉換紅外光譜比較鍵結種類的多寡以及材料間隙大小量測以及光致發光的探討，並對其衍伸出對非結晶半導體材料的能階、缺陷數、鍵結種類的探討

In this thesis, we use some optical techniques to analyze characteristics of semiconductor: epitaxial SiGe, Al2O3 passivated silicon, and amorphous silicon. In order to reduce the cost of fabrication, utilizing photoluminescence to examine the quality and defects of interface becomes one of essential method. Besides, some of methods to obtain optical properties are discussed. First part of this thesis, the carrier gas effects on epitaxial SiGe would be observed. Different carrier gas or precursor would causes not only distinct quality of SiGe but also different growth rate. Besides, the Ge concentration of SiGe also be influenced by these two factors. All of these properties are of importance in fabrication of devices. Hence, in this thesis, SiGe grown using either SiH4 or DCS as precursor and N2 or H2 as carrier gas would be demonstrated. Second, new methods to form Al2O3 passivated silicon would be demonstrated. First, the Al2O3 formed by oxidizing aluminums would be discussed. Next, Al2O3/ TiO2 stack layers deposited by atomic layer deposited to improve the quality of single Al2O3 film is also demonstrated. Finally, Photoluminescence and Quasi-Steady-State Photoconductance measurements are implemented to examine the qualities of passivation layers. Third, the optical properties of hydrogenated amorphous silicon(a-Si:H) films are demonstrated. In this thesis, the influences of H2 dilution for depositing a-Si:H would be discussed. Tauc plot method would be demonstrated to investigate the optical bandgap of a-Si:H films. Also, Fourier Transform Infrared (FTIR) spectrometer are used distinguish the void size of different a-Si:H. In the end, the passviation qualities of the a-Si:H films are also demonstrated.