利用奈米壓印微影及氫化物氣相磊晶技術成長氮化鎵之研究

Abstract

本論文中使用奈米壓印技術，製造具有陣列孔洞結構之氮化鎵薄膜。經過壓印製程，我們將所設計的圖案晶卻轉移至高分子阻劑PMMA上，藉由PMMA為蝕刻遮罩，再依序使用反應式離子蝕刻和電感耦合電漿蝕刻製作出陣列孔洞結構的氮化鎵薄膜，接著使用氫化物氣相磊晶系統二次成長氮化鎵材料，經由參數的調變，我們找到適合此奈米級孔洞基材成長的條件和趨勢。由螢光光譜和X射線繞射儀的量測可以證明利用此結構成長之氮化鎵材料，磊晶品質得到改善，且缺陷密度也減少為一般氮化鎵模板所成長之氮化鎵材料的一半，約為8.3×107 cm-2。

A gallium nitride (GaN) thin film with nanoscaled porous array structure was fabricated using nanoimprint lithography (NIL) method in this study. This obtained nanoarray was conducted using step-by-step pattern transformation strategy combined with top-down lithography on a multi-layer materials consisting of conventional PMMA, silica dioxide (SiO2), and GaN template from top to bottom. During the synthetic processes, reactive ion etcher (RIE) and induced coupled plasma (ICP) techniques were introduced in order to confine the etching speed on different mediates for optimizing the quality of patterns. After the NIL processes, GaN was grown by hydride vapor phase epitaxy (HVPE). Using the proposed technique with optimized experimental parameters, strategies fabricating the nanoscaled array patterns on GaN with expected structures were successfully developed. Results of photoluminescence (PL) and x-ray diffraction (XRD) clearly exhibited that our experimentally obtained samples with improved quality and reduced defect density (8 x107 cm-2), which is about a half of that fabricated by conventional GaN template.