砷銻化鋁化合物的成長及其異質結構和遠紅外線帶通濾波器的研究

Abstract

本文分為兩個部份，首先探討以常壓有機金屬氣相磊晶法(MOCVD)，成長 砷化鋁、砷銻化鋁及砷化銦鎵化合物薄膜。本實驗所成長的最佳砷化鋁薄 膜，磊晶溫度為500℃，V/III值為20。固定磊晶溫度為500℃，當V/III值 降低時，砷化鋁薄膜的晶格常數會隨著V/III值降低，而偏離正常的晶格 常數。在成長砷銻化鋁薄膜時，實驗結果顯示，砷的固相組成和TBAs/ TMAl的比值呈線性關係，且由拉曼光譜實驗，LO模的peak強度皆大於TO模 的peak強度，顯示砷銻化鋁有很好的薄膜品質。至於砷化銦鎵方面，在 Xs(In)=0.53，即砷化銦鎵與基板磷化銦晶格完全匹配的情況下，可獲得 最佳薄膜品質，其X-ray的半高寬僅有49arcsec。第二部份是在砷化鎵基 板上成長銻化銦薄膜，並以此作為吸收層材料，配以常用之多層膜結構模 擬研究遠紅外線帶通濾波器(band-pass filter)。首先利用特徵矩陣( characteristic matrix)法，寫成電腦程式，希望藉著電腦模擬以尋求一 最有效且層數最少的多層膜結構。新的濾波器將可以消除傳統多層膜濾波 器高雜訊背景光之缺點。最重要的是因整個濾波器膜厚有效降低，製作工 作時間因而可以大幅縮短，減低生產成本。此一新型濾波器研究成熟後， 應對國內紅外線遙測相關科技產業發展有所裨益。 In this study, we have grown AlAs, AlAsSb, InGaAs and their heterostructuresfor the study of single-barrier tunneling diode using atmospheric pressure me-talorganic chemical vapor deposition. Experimental results indicates that op-timum AlAs film quality can be obtained at 500℃ when TBAs is used as As sour-ce precursors. For AlAsSb growth, unlike conventional strong non-linear solid-gas phase diagram, a linear relationship was found between solid As/Al solid composition and input TBAs/ TMAl gas ratio, which greatly simplify the composition control during the AlAsSb sample preparation. In addition, an InGaAs alloyis also studied. A nearly perfect InP-lattice-matched InGaAs film was obtained at 600℃ with V/III=100 and TMIn/(TMIn+ TEGa)=0.55. The corresponding FWHM of X-ray rocking curve is as narrow as 49 arcsec. Besides thin film growth, a far-infrared band-pass filter for the sensing of human body radiation (10 mm) is also investigated. Differing from the traditional interfere filter, this novelfilter consists an additional InSb absorption layer to suppress the backgroundnoise at the short wavelength region. This is primarily attributed to low bandgap characteristic of InSb (0.17 eV), such that a photon with energy > 0.17 eV is absorbed effectively in InSb absorption layer. We believe the combination of multi-layer dielectric coating and InSb absorption layer will bring some important interests for the remote sensing industry.