Zn在GaAs,InP.GaP半導體中的快速熱擴散

Abstract

本論文主要在探討Zn原子在GaAs,InP和GaP 半導體中的快速熱擴散現 象.Zn/SiO2和ZnO/SiO2薄膜以共濺鍍(co-sputtering)方式,沈積在半導體 基底上作為固體擴散源。而雜質的擴散分佈是由二次離子質譜儀(SIMS)來 檢測;雙晶x-ray繞射(DCXD)和拉曼光 譜的量測主要 是用來作為雜質經濺鍍和擴散之後的晶格匹配和樣品表面的重構分析. 基於取代-擠壓機制的模型,我們發現在快速熱程序(RTP)時,Zn的擴散主要 決定於溫度的變化過程.基底和擴散源間熱膨脹係數的差異所造成的應力 為加強Zn在基底中擴散的主要因素.由DCXD的結果顯示摻有Zn的GaAs和GaP 樣品晶格匹配,而在InP的樣品中其晶 格不匹配程度可 達1.5*10-4.由拉曼光譜顯示當650C,15秒快速熱擴散時對濺鍍有Zn/SiO2 和ZnO/SiO2薄膜的GaAs基底表面有退火的作用. In this thesis work,we studied the rapid thermal diffusion behavior of Zn atoms in GaAs,InP,and GaP semiconductors.Zn/SiO2 and ZnO/SiO2 films were co-sputtered onto the semiconductor substrates as diffusion sources in solid-phase form. The impurity distribution profiles were examined by secondary- ion- mass spectrometry(SIMS). Double crystal x-ray diffraction (DCXD) and Raman spectroscopy were performed to analyze the conditions of lattice mismatching and surface reconstruction of samples after diffusion and puttering. Based on substitutional-interstitial model, we verify that the Zn diffusionprocess is strong controlled by the temperature history during rapid thermal process. The strength of stress due to the significance of thermal expansiondifference between substrates and diffusion-source films was attributed to the main factor to enhance the Zn diffusion in the substrates. The DCXD resultsindicate well lattice-matching of Zn-doped GaAs and GaP samples,while thelattice-mismatching degree can reach to 1.5*10-4 for Zn-diffused InP substrates.Raman spectra reveal that the rapid thermal process at 650C for 15sec can improve the surface quality of GaAs substrate with Zn/SiO2 and ZnO/SiO2 deposition.