｜飛秒脈衝雷射濺鍍技術與應用

摘要：雷射脈衝濺鍍（Pulsed Laser Deposition：PLD）技術可以在低溫下沉積各種薄膜包括成分複雜的多元化合物例如超導材料（YBaCuO）或耐磨的類鑽石膜（diamond-like carbon：DLC）...等等，而且沉積膜與靶材的化學劑量比（stoichiometry）幾乎可達一致而備受矚目。但是傳統使用Excimer或Nd:YAG雷射鍍膜時會因雷射脈衝太長，靶材受熱過久而產生微米級的噴濺物（particulate）沉積於薄膜上，影響薄膜品質。許多避免微米級顆粒產生以改善膜的品質的方式被提出，而超短脈衝雷射則被認為是可以大幅解決此項問題。本文將介紹飛秒雷射PLD與奈秒雷射PLD的差異，並對工研院南分院雷射應用科技中心與日本東北大學共同合作的飛秒脈衝雷射濺鍍技術應用於ZnO沉積的研究成果與以介紹。

Abstract: Pulsed laser deposition (PLD) technology has been widely used in low temperature deposition of complex compound oxide such as YBaCuO, wear resistant diamond like carbon (DLC)...etc. Moreover, PLD allowed the stoichiometry transfer of multicomponent target to deposited film has attracted lots of attention. For using long pulsed ns laser such as excimer or Nd:YAG laser for PLD, the main drawback is the deposition of micrometer size droplets which have degrade the film quality dramatically. Many methods have been designed to solve this issue and ultra-short pulse laser is considered that can greatly reduce the micro-meter size droplets. This paper reviews the difference between femtosecond PLD and nanosecond PLD of thin films. The result of the joint research collaboration between ITRI-South, Taiwan and Tohoku University, Japan on the application of femtosecond pulsed laser deposition technology of ZnO deposition will also be presented.

關鍵詞：脈衝雷射濺鍍、飛秒雷射、氧化鋅

Keywords：Pulsed laser deposition, Femtosecond laser, ZnO

前言
雷射脈衝濺鍍（Pulsed Laser Deposition：PLD）技術是利用高功率的雷射光束，聚焦在位於真空腔體內的靶材上，使材料表面因受雷射照射而吸收能量導致材料瞬間氣化，產生具有高動能的等離子羽狀物（plasma plume），向待鍍基板噴射而形成薄膜沉積。本技術在紅寶石雷射發明後不久即被提出，但一直要到Dijkamp et al（1987）成功的將高溫超導材料YBa₂Cu₃O₇利用PLD沉積後，本技術才獲得普遍讚譽，並吸引了廣泛的注意。過去二十幾年，PLD已經被工業界與學術界大量採用[1]，有24162篇關於PLD的論文被發表。包括陶瓷氧化物、氮化物膜、金屬多層膜、各種超晶格（superlattices）、有機薄膜...等等都可以用PLD來製作。因此，薄膜製造在工業上可以說已邁入新紀元。