Co掺杂含量对SiC薄膜磁性能的影响
毕业论文关键词：稀磁半导体；SiC；铁磁性；退火
Effect of Co Doping on The Magnetic Properties of SiC Films
Abstract: Diluted magnetic semiconductors spintronics, as a representative of this new field, which has not only a magnetism, but also has properties of semiconductors. And it has potentially significant value, while SiC material as an important wide band gap semiconductor, has its broad application. This paper mainly adopted by RF magnetron sputtering to prepare Co doped with different concentrations of SiC semiconductor films using XAFS (X-ray absorption fine structure technique), SEM (scanning electron microscope), XPS (X-ray photoelectron spectroscopy) and XRD ( X-ray diffraction) of the films structure, composition and morphology that were studied, and multi-function physical testing system (PPMS) to study the magnetic thin film. The results show that after 1200℃ annealing, the formation of a 3C-SiC film structure, while generating Co-Si compound, with the incorporation of increasing the concentration of Co, the film gradually becomes rough surface. Co doping concentration from 2At% to 8At%, the saturation magnetization increases with the film, but when the Co concentration was incorporated 10A%, the saturation magnetization decreased. Preparation of state film annealed at 800℃ thin ferromagnetic significantly enhanced, and after annealing at 1200℃, ferromagnetic gradually becomes weakening. The film observed by ferromagnetism at room temperature is intrinsic.
Key Words: Diluted Magnetic Semiconductors; SiC; Ferromagnetism; Annealing
引言
随着人们对信息的处理，传输和储存一体化的要求日益增强，而传统的材料很难满足这一要求，寻找一种新的材料来满足这一要求是科学家们十分迫切的追求。在过去科学家们的探索中我们可知，在半导体材料中，信息处理利用的是电荷的电荷属性，而信息储存利用的是电荷的自旋属性[1]。电荷自旋的载体是电子，而电荷的载体也是电子，即电子具有这双重性质，因此想到利用电子构造出将磁和电结合在一起的半导体器件，即处理信息和存储信息同时进行，这将极大的提高处理信息的速度和增大存储信息的密度。
稀磁半导体(DMS)[2]就是将3d或5d TM[3]离子引入到半导体材料中，使其既具有半导体材料优良的电学特性，又具有磁性材料的优良磁学特性[2]，即同时具有电荷属性和自旋属性，从而成为自旋电子[4]材料的重点研究对象。论文网
1.SiC稀磁半导体
SiC具有许多优良性质无论是在物理性质方面还是在化学性质方面；它是现阶段发展最为成熟的宽禁带半导体材料[1]；同时也是目前正在发展中的新一代半导体材料。在SiC晶体中，Si原子和C原子以共价键结合，每个Si原子与四个C原子以共价键结合，而每个C原子也与四个Si原子以共价键结合[5]，结构稳定，因而SiC晶体具有很多优异的物理性能，例如能抗强的腐蚀性，耐高温、高载流子饱和迁移速度等[6]，在抗辐射方面、高温方面等也具有很大的应用前景[7]。Si原子和C原子在不同的物理化学条件下可以在结构上形成同质异型体，对同质异型体都有相同的化学性质不同的物理性质。目前发现SiC晶体有250多种同质异型体，例如，12H-SiC [8-10]。
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