本研究藉由調整製程參數以製備壓縮及拉伸應變鍺薄膜，參數包括工作壓力、主磁場電流及GeH4流速，並利用Ｘ光繞射儀、原子力顯微鏡、蝕刻缺陷密度量測法、近紅外光光譜儀等等，探討其薄膜特性及近紅外光波段吸收係數變化。研究結果顯示利用電子迴旋共振化學氣相沉積法可得拉伸應變含量最高為0.17% 的矽基鍺薄膜，其X光繞射半高寬可達646 arcsec，表面粗糙度方均根值為4.9 nm，差排缺陷密度約106 #/cm2。為了進一步提升拉伸應變及改善薄膜磊晶品質，將鍺薄膜進行後退火處理，發現其拉伸應變可提升至0.25%，半高寬降低為 456 arcsec。此外本實驗利用光譜儀量測近紅外光波段壓縮及拉伸應變兩種薄膜的吸收係數，拉伸應變鍺薄膜相較於壓縮應變鍺薄膜在吸收光波長1550 nm時，吸收截止波段紅位移平均可達120 nm，並將此製作成P-I-N結構，量測低負偏壓下吸收係數變化 (Δα/α)，其隨著負偏壓上升而增加，Δα/α在負偏壓0至3V為1.3。;We use Electron Cyclotron Resonance-Chemical Vapor Deposition (ECR-CVD) to grow compressive and tensile strained Germanium (Ge) thin films on Silicon (Si) substrate under the low temperature of 220℃ in this research. The fabrication of device on Complementary Metal-Oxide-Semiconductor (CMOS) is only for low temperature less than 400℃, so ECR-CVD is a suitable method to integrate with devices. On the other hand, we can deposit strain-controlled Ge thin films on Si substrate by ECR-CVD. We can use the method to adjust the value of the band gap of Ge. This research indicates that there is a higher absorption coefficient between the wavelength of 1500 nm to 1600 nm compared with bulk Ge.
In this research, we change the parameters of the system of ECR-CVD including working pressure, mail coil current and the flow of GeH4. We measure the thin films by XRD, AFM, EPD , UV spectrophotometer and so on. We analyze the red shift of wavelength and the properties of the Ge thin films on Si. The research indicates the tensile stress of Ge thin films are up to 0.17%. The FWHM is 646 arcsec. The roughness is 4.9 nm and the threading dislocation density is about 106 #/cm2. In order to increase the tensile strain, we post anneal this Ge thin film. The tensile strain enhance to 0.25%. The FWHM become 456 arcsec. We also measure the Ge thin films by UV spectrophotometer. There is a 120 nm red wavelength shift of absorption coefficient in 1550 nm compared with compressive strained Ge. Then we fabricate the P-I-N structure with this Ge thin film. Under reverse bias 0V to 3V, we measure the value 1.3 of variety of absorption coefficient.
