分子束磊晶成長單斜晶系氧化釓於(0001)氮化鎵基材之特性研究

Structural Investigation of Monoclinic Phase Gd2O3 Epitaxially grown on GaN (0001) by MBE

李志勛(Chih-Hsun Lee)

指導教授 ： 洪銘輝 ； 郭瑞年

國立清華大學/工學院/材料科學工程學系/碩士(2008年)

https://doi.org/10.6843/NTHU.2008.00477

摘要

經由分子束磊晶技術，高品質奈米尺寸單晶氧化釓薄膜成功地磊晶 在(0001)晶面的氮化鎵基材上。 利用同步輻射高亮度、高解析度Ｘ光繞射技術，以及高解析度穿透 式電子顯微鏡技術，可有效地研究超薄磊晶薄膜之結構特性。臨場 反射式高能電子繞射的圖形亦幫助我們來了解磊晶成長時薄膜之結 構形態。磊晶高介電之氧化釓薄膜之電性分析在此研究中也將討論到。 此磊晶氧化釓薄膜具有高溫相的單斜晶結構，以(012)平面於(0001) 晶向之氮化鎵基材上磊晶成長，在平面上則以氧化釓 [020] //氮化 鎵 [1120]的結晶方向為主。高溫退火後具有極佳的漏電流密度，約 為4.6×10-9安培╱平方公分，可能與實驗觀測到的晶粒成長有關。

關鍵字

單斜晶 ； X光散射 ； 繞射 ； 分子束磊晶 ； 氧化釓 ； 氮化鎵

並列摘要

High-quality single-crystal Gd2O3 nano films have been grown epitaxially on GaN (0001). The films were electron beam evaporated from powder-packed and sintered Gd2O3 target at a substrate temperature of 700°C by molecular beam epitaxy (MBE).
Structural studies were carried out by x-ray diffraction using a synchrotron radiation source, and cross sectional high-resolution transmission electron microscopy (HRTEM). The growth was in-situ monitored by reflection high energy electron diffraction. Electrical measurements of I-V and
C-V characteristics were also carried out.
The films adopt the high temperature monoclinic phase with six domains. The films are well aligned with the
GaN substrate with an orientation relationship of
Gd2O3 (012)m // GaN (0001), and a dominant in-plane expitaxy of Gd2O3 [020]m // GaN [1120]. Excellent leakage performance (JL~4.6x10-9 A/cm2 at 1MV/cm) is observed after 1100oC RTP, possibly due to a significant domain size increase by ~ 3 times as revealed by grazing incidence x-ray diffraction data together with the Williamson-Hall plot analysis.

並列關鍵字

Monoclinic ； X-ray scattering ； Diffraction ； Molecular beam epitaxy ； Gd2O3 ； GaN

參考文獻

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