Studies on Heteroepitaxial Growth of III-V Diluted Magnetic Semiconductors on Si Substrates

Si衬底上III-V族稀磁半导体异质外延生长研究

基本信息

批准号：
14550005
负责人：
UCHITOMI Naotaka
金额：
$ 2.37万
依托单位：
Nagaoka University of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2004
项目状态：
已结题

项目摘要

The III-V-based diluted magnetic semiconductor (Ga,Mn) As is one of the most promising materials for potential use in spintronic devices. (Ga,Mn) As is usually grown on GaAs substrates using low temperature molecular beam epitaxy (MBE), and has been combined with 4-6% Mn ions for metallic-phase ferromagnetism.We investigated the growth of diluted magnetic semiconductor (DMS) (Ga_<1_x>, Mn_x) As epitaxial layers on n-type Si(100) substrates using low-temperature-molecular beam epitaxy (LT-MBE). The Mn content of the (Ga_<1_x>, Mn_x) As layers was relatively high (6.2%). The ferromagnetic transition temperature Tc was estimated to be 80 K for the as-grown film, and it strongly depended on the annealing temperature. The p-(Ga, Mn) As/n-Si heterostructures showing a ferromagnetic nature indicated a change in the sign of the Hall coefficient. We found that the transition temperature from n-type to p-type conduction considerably correlates with the Tc. We also studied the properties and annealing effects of substrate-free (Ga,Mn) As films prepared by etching Si substrates from (Ga,Mn) As/Si structures, and compared the results with those from (Ga,Mn) As/Si heterostructures. The substrate-free (Ga,Mn) As films with 6% Mn content were annealed at 250 degree C as a function of time. From Hall-effect measurements, the Curie temperature of substrate-free (Ga,Mn) As films was estimated to be 87 K for an as-grown film, enhanced up to 152 K after low temperature annealing for 60 min. We found that the (Ga,Mn) As films grown on Si substrates show a relatively high Curie temperature.

III-V 族稀磁半导体 (Ga,Mn) As 是自旋电子器件中最有前景的材料之一。 (Ga,Mn) As 通常使用低温分子束外延 (MBE) 在 GaAs 衬底上生长，并与 4-6% Mn 离子结合以获得金属相铁磁性。我们研究了稀磁半导体 (DMS) 的生长(Ga_<1_x>, Mn_x) 使用低温分子束外延 (LT-MBE) 在 n 型 Si(100) 衬底上作为外延层。 (Ga_<1_x>，Mn_x)As层的Mn含量相对较高(6.2％)。对于生长的薄膜，铁磁转变温度 Tc 估计为 80 K，并且它很大程度上取决于退火温度。显示出铁磁性质的 p-(Ga, Mn) As/n-Si 异质结构表明霍尔系数的符号发生了变化。我们发现从 n 型到 p 型传导的转变温度与 Tc 显着相关。我们还研究了通过从(Ga,Mn)As/Si结构蚀刻Si衬底制备的无衬底(Ga,Mn)As薄膜的性能和退火效果，并将结果与(Ga,Mn)As/Si结构的结果进行了比较。异质结构。 Mn 含量为 6% 的无衬底 (Ga,Mn) As 薄膜在 250 摄氏度下随时间进行退火。根据霍尔效应测量，生长薄膜的无衬底 (Ga,Mn) As 薄膜的居里温度估计为 87 K，在低温退火 60 分钟后提高到 152 K。我们发现在Si衬底上生长的(Ga,Mn)As薄膜表现出相对较高的居里温度。