沉積角對氟化鎂薄膜於光學、殘留應力及微結構特性之影響

Abstract

近年來，由於光電領域技術與應用的蓬勃發展，薄膜技術也隨之重要。由於薄膜中殘留應力的存在，對光電元件及系統的功能會產生很大的影響，它不僅會導致薄膜龜裂、脫落，還會作用於基板，使基板發生形變，進而影響傳輸特性、降低了可靠性。因此，探討光學薄膜中的殘餘應力，並瞭解如何量測光學薄膜的物理特性是非常重要的課題。 本研究以斜向沉積之氟化鎂（MgF2）光學薄膜為研究對象，利用電子槍蒸鍍法以不同的沉積角度製備MgF2光學薄膜，探討其在光學特性、殘留應力以及在表面形貌和微結構方面所造成的影響。實驗儀器是以UV/VIS分光光譜儀檢測其光學特性，利用自製之Twyman-Green干涉儀及相位還原法執行殘留應力量測的曲率擬合及數值分析。並藉由掃瞄式電子顯微鏡、原子力顯微鏡以及顯微干涉術進行微結構和表面粗糙度的觀測。

It is well known that mechanical stresses can be found in almost all thin films. In general, optical thin films process results in residual stress and it may cause buckling of the thin films or deformation of the substrate. Residual stress is a very important issue because the substrate bending and deformation caused by the residual stress can be related to the performance of thin films. In this study, the influence of different deposition angles on optical properties, residual stress and microstructure of magnesium fluoride (MgF2) thin films is investigated. E-beam evaporation method was used to prepare MgF2 thin films with two different columnar angles. The transmittance spectrum and residual stress were measured by a UV/VIS spectrophotometer and a home-made Twyman-Green interferometer, respectively. In addition, we used scanning electron microscope (SEM), atomic force microscope (AFM) and interferometric microscopy to observe surface morphology and roughness of MgF2 thin films.