【作者】 贺晓彬；

【导师】 杨瑞霞；

【作者基本信息】 河北工业大学 ， 微电子学与固体电子学， 2007， 硕士

【摘要】 GaAs材料在各种电学器件、光学器件中具有广泛适用性,基于GaAs的稀磁半导体也倍受关注。通过离子注入法制备的含有MnAs、MnGa磁性粒子的GaAs基磁性半导体的居里温度Tc可以超过300K,使这种材料在室温下显示出磁性。本论文主要研究了控制注Mn的GaAs中MnAs或GaMn亚微米磁性粒子的大小、分布以及密度的工艺措施。用离子注入的方法将Mn离子直接注入到GaAs衬底中,然后通过退火处理,成功制备出含有MnAs、MnGa二相粒子的GaAs基磁性半导体。用原子力显微镜、磁力显微镜、二次离子质谱等方法较系统地研究了退火条件和注入条件对MnAs、MnGa粒子的影响,发现退火条件会影响MnAs或GaMn亚微米磁性粒子的大小、分布以及密度。在退火温度的选择上采用了650℃、850℃以及先500℃然后850℃三种。通过实验发现经过650℃退火后的样品中形成直径小、密度大的MnAs、MnGa第二相团簇,而在850℃下退火的样品中形成的第二相团簇的直径较大,但是密度较小,这主要是因为温度较低时,Mn在GaAs中的迁移率也较小,因此扩散比高温下困难,所以会有更多的MnAs成核点且容易均匀成核,就形成了直径小、密度大的第二相团簇。使用原子力显微镜分析了退火条件对样品晶格结构的影响。发现采用先在500℃下退火5秒然后再在850℃下退火20秒两步退火的方法可以使样品晶格结构得到较好的恢复,MnAs、MnGa粒子直径小、密度大。通过二次离子质谱分析发现经过两步退火的样品中Mn的外扩散现象要比直接850℃退火的样品轻。这主要是由于注入层非晶化或微晶化,有利于杂质的快速扩散,在两步退火时,第一步退火已经使非晶层中的空位已经有一部分消失,因此Mn的扩散就会受到抑制。更多还原

【Abstract】 New hybrid devices coupling magnetic and conduction properties can be fabricated by different ways to control and to manipulate both the charge and the spin of carriers. Due to the wide application of GaAs material in high speed electronic devices and photoelectric devices, the GaAs base diluted magnetic semiconductor is paid more attentions. Ferromagnetic MnAs and MnGa in GaAs with the Curie temperature above 300 K, by ion implantation with subsequent annealing, have attracted a great deal of interest because of their possible applications to the semiconductor spintronics.In this thesis, the effect of annealing on the MnAs and MnGa clusters in GaAs was studied. Mn ion was implanted into GaAs substrates ,and MnAs or MnGa phase which show ferromagnetism were formed by annealing at 650℃-900℃. In order to research effect of annealing on the MnAs and MnGa clusters in GaAs, Atom Force Microscope(AFM), Magnetic Force Microscope (MFM), Secondary Ion Mass Spectrometry(SIMS) were employed. It was found that size distribution and densities of MnAs and MnGa clusters was affected by annealing conditions. The implanted samples were annealed at temperatures 650℃and 850℃,in the other case a pre-anneal was performed at 500℃,after that the samples were annealed at 850℃. The measurements showed that in the case of 650℃annealing, MnAs and MnGa clusters was small and dense .The AFM measurements show that the crystal lattice structure will be restored after annealing, and the crystal lattice structure of sample after two-step annealing was better than the sample after single annealing. The distributions of Mn in annealed samples were measured by Secondary Ion Mass Spectrometry, it is showed that the temperature of annealing has great affection on the distribution of Mn in sample.更多还原