利用原子層沉積儀成長鋁摻雜氧化鋅磊晶薄膜

Abstract

本論文研究利用原子層沉積法成長非極化性(non-polar)磊晶鋁摻雜氧化鋅薄膜在m-plane(101 ̅0)藍寶石基板上。其目的為發展能成長於c軸取向氧化鋅奈米柱之側壁上之薄膜，並組合形成p-n介面的發光二極體元件，以提高發光效率。本研究利用改變不同摻雜比例的鋁，分別為1:9、1:15和本質氧化鋅薄膜，在真空退火300℃、400℃、500℃、600℃、700℃及750℃來探討其特性。分析方面，使用同步輻射X-ray八環繞射儀研究薄膜結構特性，薄膜電學特性使用van der pauw method霍爾量測探討載子濃度、載子遷移率、電阻率和霍爾電壓，採用光激螢光光譜進行10K至300K之變溫實驗以探討載子躍遷，X-ray光電子能譜分析鋁摻雜氧化鋅薄膜濃度大小。由XRD的分析指出，我們成功成長出磊晶薄膜，其在m-plane藍寶石基板之關係為(101 ̅0) <0001>ZnO || (101 ̅0) <1 ̅21 ̅0>sapphire。由Hall結果發現本質氧化鋅薄膜載子濃度約在1019cm-3，鋁摻雜氧化鋅薄膜提升一個數量級達1020cm-3，且電阻率亦有明顯的下降。從光致螢光結果得知AZO薄膜發現有S曲線的現象發生，其可能原因來自於未經退火時的鋁濃度為層狀分佈，藉由退火使得鋁原子的分佈在各層上下擴散，改善S曲線的現象。

We utilize the atomic layer deposition method to deposited nonpolar epitaxial Al-doped ZnO thin films on (101 ̅0) M-plane sapphire substrate. The purpose of this research which was try to understand the growth conductions and doping mechanism for for ZnO thin films on side well of nanorod. In this work, we characterize the properties of ZnO thin films include undoped, 1:9 and 1:15 ratio ZnO:Al thin films and annealing in vacuum from 300 to 750 degree. For analysis, we use synchrotron 8-circle diffractmeter, Hall measurement, photoluminescence and x-ray photoemission to obtain the crystal structure, concentration, resistivity, mobility, carrier dynamics and Al composition. XRD analysis indicates that we have successfully grown the epitaxial film, and its relationship m-plane sapphire substrate is (101 ̅0) <0001> ZnO | | (101 ̅0) <1 ̅21 ̅0> sapphire.Hall effect analysis indicates the carrier concentration of Zinc oxide thin film is 1019cm-3 . The Al-doped ZnO thin films elevate an order of magnitude up to 1020cm-3, and the resistivity is significantly reduced. Obtained from photoluminescence, we found the S-shaped from varshini plots for AZO thin films. That is, the aluminum concentration is not uniform across the layers for unannealing AZO thin films. But we can improve aluminum concentration by annealing method.