石英上覆矽 (Silicon on Quartz, SOQ) 因其優越的材料特性，將是未來應用於研製高效能與省電的先進電子或光電元件不可獲缺的材料之一。雖然已有幾篇文獻指出一些製作SOQ晶圓可行的方法，但是這些方仍存在著許多缺點，還需更進一步的改善。在本篇論文研究，主要是開發出，以一創新製程方法，在低溫下將一厚度可被控制的單晶矽薄膜轉移至石英上製作出SOQ晶圓，而不需使用到傳統的背向蝕刻或離子佈植製程。此創新製程最關鍵的步驟就是，在電漿氫化過程中，應用磊晶矽層與深埋硼鍺摻雜矽層之間的界面，而使擴散氫離子可被捕捉住在特定深度的磊晶界面處。被電漿氫化過後的試片馬上以電漿活化晶圓鍵合技術與另一石英晶圓鍵合在一起，再施以150 °C退火來增加鍵合強度。之後經由180 °C退火而使磊晶界面處產生許多初始微裂縫，接著使用機械力誘導，迫使破裂面延著脆弱的磊晶界面進行，而成功的在室溫下將單晶矽薄膜轉移至石英上。從二次離子質譜儀結果可知，有大量的擴散氫離子聚集在磊晶界面處。由橫截面TEM與SEM圖可觀察出，在石英上的轉移單晶矽層大約有715奈米的厚度，而這厚度也約與一開始在硼鍺摻雜矽層上的磊晶矽層厚度一致，且此轉移矽層的沒有任何的晶格損傷。根據AFM的量測結果指出，最終的SOQ表面是相當的光滑平整。本次實驗能成功在低溫下將單晶矽薄膜轉移至石英上而製作出SOQ材料主要的因素可能是在於，磊晶界面處存在有大量的硼摻雜，因為硼有吸附複數個氫離子的能力且硼又可當做催化劑降低表面剝離或是薄膜轉移的溫度。 Silicon on quartz (SOQ) wafer depending on its superior characteristics is an excellent candidate for fabricating future advanced electronic or electro-optical devices with high performance and low power consumption. Although previous reports have demonstrated several feasible methods for manufacturing SOQ wafers, some disadvantages still remain and need to be improved. In this study, an innovative approach has been developed to transfer a thickness-controlled single-crystalline thin Si layer at low temperature for the fabrication of SOQ wafers without using etch back or ion implantation process. The technique utilized the interface between an epitaxial Si layer over a buried Boron/Germanium (B/Ge) doped Si layer to provide hydrogen trapping sites at a specific depth during plasma hydrogenation. The hydrogenated epitaxial Si wafer was subsequently bonded to another quartz wafer using plasma-activated wafer bonding technique, followed by thermal annealing at 150 oC so as to enhance the bonding strength. Successful Si layer transfer from epitaxial Si wafer onto quartz wafer was conducted by initial microcrack formations at the interface after annealing at 180 oC and subsequent mechanically induced crack propagations along the interface at room temperature. Diffusing hydrogen ions could accumulate enormously at the interface, as indicated from SIMS result. Cross-sectional TEM and SEM have shown that the thickness of the transferred Si layer on quartz, ~715nm, was almost consistent with that of the epitaxial Si layer over B/Ge doped Si layer and the top transferred Si layer was free of lattice damage. According to AFM measurement, the surface of final SOQ was smooth and uniform. The existing heavy boron dopants at the interface region are believed to contribute to this successful low temperature layer transfer for making SOQ materials and, as a result, that boron could attract multiple hydrogen ions and serve as a catalytic to alleviate annealing temperature for surface blistering or layer splitting.
