Investigations on Structure and Magnetic Properties of Ga1-xMnxAs Fabricated by Ion Beam Induced Epitaxial Crystallization

利用離子束誘發晶體結晶技術製作砷化鎵錳之結構與磁性特性分析

陳建旭(Chien-Hsu Chen)

指導教授 ： 齊正中 ； 吳秀錦

國立清華大學/理學院/物理學系/博士(2009年)

摘要

本篇論文主要是在討論以離子束誘發晶體結晶技術(ion beam induced epitaxial recrystallization, IBIEC)來製備硫化鋅結構之單晶砷化錳鎵(Ga1-xMnxAs)。製作的方式是以錳離子佈植掺雜錳原子至砷化鎵基材裡，然後以離子束照射的方式修補錳離子佈植時所產生的晶體損傷。

然而錳在砷化鎵裡的熔解度很低並且會隨著溫度的上升而遞減，所以在高溫退火時錳原子都會析出並產生非硫化鋅結構之砷化錳鎵或是其他含錳合金。所以本篇論文的重點係在證明以離子束誘發晶體結晶技術製作的砷化錳鎵是閃鋅礦之單晶結構。本篇文在一系列的物理與化學性質之結構分析後，證明離子束誘發晶體結晶技術所製備的砷化錳鎵為閃鋅礦之單晶結構。

除晶體結構的物理與化學特性之外，本論文中利用超導量子干涉儀、同步輻射與磁力顯微鏡分析砷化錳鎵的磁性特性。其實驗結果確認以離子束誘發晶體結晶技術製備的砷化錳鎵具有室溫鐵磁性。

關鍵字

稀磁性半導體 ； 砷化鎵 ； 離子佈植 ； 離子束誘發晶體結晶 ； 離子束照射

並列摘要

This is a study on structure and magnetic properties of Ga1-xMnxAs fabricated by ion beam induced epitaxial recrystallization (IBIEC). In this thesis, the Ga1-xMnxAs thin film was made by Mn implantation into GaAs wafer and following ion beam irradiation.

But it is notorious that Mn implanted GaAs usually has 2nd phase precipitation due to the Mn solubility of GaAs is low at high temperature annealing. Ion beam induced epitaxial recrystallization is a unique technique to regrowth damage crystal at low temperature. So we applied this technique to prepare the Ga1-xMnxAs thin film. This thesis was focus on the exclusion of the existence of 2nd phase and tried to identify the local structure of Mn implanted GaAs. In order to clarify the annealed Mn-implanted GaAs was the single phase zincblende Ga1-xMnxAs compound, a series of analyses (Channeling, TEM, XRD, SIMS XAS etc) were made to study its structure. It was proven that the structure of IBIEC treated Mn implanted GaAs form the Ga1-xMnxAs structure, i.e. Mn atoms substitute Ga atom and form zincblende type Ga1-xMnxAs.

The magnetic properties were measured by Superconducting Quantum Interference Device (SQUID) magnetometry, X-ray Magnetic Circular Dichoism (XMCD) and Magnetic force Microscopy (MFM). The results confirmed that the Ga1-xMnxAs prepared by Mn implantation and following IBIEC treatment has room temperature ferromagnetism.

並列關鍵字

diluted magnetic semiconductors ； GaAs ； manganese ； ion implantation ； ion beam induced epitaxial recrystallization ； ion beam irradiation

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