矽錳稀磁半導體之磁性與電性研究

The Study of MnxSi1-x DMS on Magnetic and Electrical Properties

黃威智(Wei-Ji Huang)

指導教授 ： 金重勳

國立清華大學/工學院/材料科學工程學系/碩士(2006年)

https://doi.org/10.6843/NTHU.2006.00246

摘要

中 文 摘 要
於本實驗中利用離子佈植製程製備矽錳稀磁半導體，並且於矽錳材料層添加硼元素來加強矽錳層的導電性，如此可確保霍爾量測訊號來自矽錳稀磁半導體層。於磁性質量測結果可知矽錳試片呈現鐵磁性表現，其磁化量可維持至高溫(~200 K)，其鐵磁性質可能源於試片中的錳原子團簇、矽錳化合物等貢獻，而非由載子誘發鐵磁性的本質稀磁半導體表現。藉由低溫霍爾量測結果亦無異常霍爾之現象表現，亦可說明其鐵磁表現可能為外質之鐵磁相訊號。於微結構、成份分析上發現矽錳化合相之析出對錳元素於矽基材中的固溶度、分佈影響甚巨，而使得矽錳試片不具稀磁半導體之本質特性。
因此於未來的矽錳稀磁半導體研究首要應聚焦於如何有效的摻雜錳原子於矽基材中而盡量避免第二相產生。

關鍵字

稀磁半導體 ； 矽錳稀磁半導體 ； 離子佈植

並列摘要

Abstract
The magnetic and structure of Si1-xMnx samples were fabricated by implanting Mn+ ions into p-type silicon (100) substrates with an energy of 150 keV at the doses of (1~10) x1015 at./cm2 and annealing at temperature ranging form 700 to 900 oC, were investigated. In the results of the magnetization against magnetic field (M-H) measurements, we found that all of the samples showed ferromagnetic characteristics in low temperature of 5 K, but the M-H loops of the samples annealed at 900 oC performed suparamagnetism at temperature of 250 K and the samples annealed at 800 oC preserved ferromagnetic properties up to 250 K. The results from magnetization as the function of temperature (M-T) measurements further approved the magnetic behaviors observed in M-H measurements. In the results of microstructure analysis implemented with TEM, we found that extremely few of Mn atoms exist in the matrix of silicon due to precipitation of second and the local structure imhomogeneity caused by Mn clusters. The imhomogeneity in distribution of Mn ions were surveyed by SIMS measurement. Moreover, we observed no phenomenon of AHE in Hall measurements, which indicated the original of ferromagnetism in our Si1-xMnx samples may come from contribution of magnetic second phases and Mn clusters.

並列關鍵字

diluted magnetic semiconductors ； silicon-based DMS

參考文獻

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