Facility Agriculture: Energy Saving and Sterilization【Department of Applied Materials Optoelectronic Engineering, National Chi Nan University / Wuu, Dong-Sing / President / Professor】
設施農業：節能栽培與滅菌【國立暨南國際大學應用材料及光電工程學系/國立中興大學材料科學與工程學系/武東星 校長/客座教授】
論文篇名
英文：Role of Interfacial Oxide in the Preferred Orientation of Ga2O3 on Si for Deep Ultraviolet Photodetectors
中文：界面氧化物對深紫外光電探測器 Si 上 Ga2O3 優先取向的作用
期刊名稱 ACS OMEGA
發表年份,卷數,起迄頁數 2021, 6, 29149-29156
作者 Chiang, Jung-Lung; Shang, Yi-Guo; Yadlapalli, Bharath Kumar; Yu, Fei-Peng; Wuu, Dong-Sing(武東星)*
DOI 10.1021/acsomega.1c04380
中文摘要 矽表面自然存在一層非晶氧化矽（SiO2），導致濺射時氧化鎵（Ga2O3）的生長不再受基板結晶度的影響。這項工作突出了在 Si 基板上形成的天然非晶奈米氧化物膜與主導為深紫外光電探測器製備的優選取向的單斜晶系 β-Ga2O3 之間的形成能。後者使用射頻濺射在 600°C 和後快速熱退火 (RTA) 沉積在具有 (111) 取向的 p 型矽 (p-Si) 上。X 射線衍射 (XRD) 結果表明對於層厚 100 nm 具有 (400) 擇優取向的沉積膜和退火後膜。然而，通過XRD和透射電子顯微鏡觀察，對於厚度為200nm並在800℃退火後減少的沉積薄膜，優選的一種與非晶結構混合了少量隨機取向。同時，產生了熱誘導的大量雙晶界（TBs）和疊差（SFs）。當在 1000°C 退火時，由於晶格應變與共格界面的關係。使用密度泛函理論計算了具有各種晶面（（001），（010），（100）和（-201））的β-Ga2O3薄膜與非晶SiO2之間的單位面積界面鍵能（Ei）。β-Ga2O3 (100)/SiO2 的 Ei 值最高，為 0.289 eV/Å2。這與沈積膜的 (100) 擇優取向一致。(100) 擇優取向是 TB 和 SF 的驅動力。響應度和光/暗電流對比度 (Iph/Idark) 的區分與非晶結構、晶界、TBs 和 SFs 成反比。因此，800°C-RTA 處理的樣品實現了最佳的金屬-半導體-金屬光電探測器性能，Iph/Idark 為 3.91×102，響應率為 0.702 A/W（λpeak = 230 nm），在 5 V 偏置下200奈米薄膜。
英文摘要 It is generally known that a layer of amorphous silicon oxide (SiO2) naturally exists on the surface of the silicon, resulting in the growth of gallium oxide (Ga2O3) no longer affected by the substrate crystallinity during sputtering. This work highlights the formation energy between the native amorphous-nano-oxide film formed on Si substrate and the monoclinic β-Ga2O3 dominating the preferred orientation prepared for deep-ultraviolet photodetector. The latter were deposited on p-type silicon (p-Si) with (111) orientation using radio frequency sputtering at 600°C and post rapid thermal annealing (RTA). The X-ray diffraction (XRD) results indicate both as-deposited and post annealing films with the (400) preferred orientation for layer thickness 100 nm. However, a little random orientation with the amorphous structure is mixed in the preferred one for the as-deposited film with thickness 200 nm and reduced after annealed at 800°C observed by XRD and transmission electron microscope. Meanwhile, thermal-induced massive twin boundaries (TBs) and stacking faults (SFs) were generated. When annealed at 1000°C, owing to the relation of lattice strain by the coherent interface. The interfacial bonding energy per unit area (Ei) betweenβ-Ga2O3 films with various facets ((001), (010), (100), and (−201)) and amorphous SiO2 was calculated using the density functional theory. The Ei ofβ-Ga2O3 (100)/SiO2 reveals the highest value, 0.289 eV/Å2. This is consistent with the (100) preferred orientation of deposited films. The (100) preferred orientation is the driving force for the TBs and SFs. The discrimination of responsivities and photo/dark current contrast ratio are inversely proportional to amorphous structure, grain boundaries, TBs, and SFs. Therefore, an optimum metal-semiconductor-metal photodetector performance is achieved for the 800°C-RTA-treated samples with the Iph/Idark of 3.91×102 and responsivity of 0.702 A/W (λpeak = 230 nm) at 5 V bias for 200 nm thin film.
發表成果與本中心研究主題相關性 Ga2O3之特殊的物理、光學、機械特性和電性，可應用於農業栽培之感測器上面，尤其可應用在深紫外光感測器、氣體感測器和螢光粉之上，能更進一步掌握植物的成長與瞬時狀態之掌握，並藉由感測器之數據給予回饋。