Measurement of 2DEG Parameters by Low‐Magnetic‐Field Hall Techniques
Measurement of 2DEG Parameters by Low‐Magnetic‐Field Hall Techniques
复制标题
利用低磁场霍尔技术测量 2DEG 参数
DOI：
10.1149/1.2096472
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发表时间：
1989
影响因子：
3.9
通讯作者：
H. Lee
中科院分区：
文献类型：
--
作者：
C. Colvard;N. Nouri;D. Ackley;H. Lee
我们已经测试了在何种程度上的HEMT结构的电阻率和霍尔系数的磁场依赖性的分析可以产生可靠的值的片密度和流动性的2DEG在存在的平行传导。我们发现，这一过程的工作相当不错，在77 K，即使是低，通常获得的磁场高达5千克。该分析是简单和有用的常规表征，它避免了繁琐的蚀刻去除的导电帽和A1 GaAs层的需要。高电子迁移率晶体管结构（HEMT）利用生长原子突变界面的能力，形成一个高度移动的二维电子气（2DEG）在两个具有不同带隙的半导体的界面。原型结构由在未掺杂GaAs上生长的Si掺杂AlxGal-xAs层组成，顶部具有高度掺杂的GaAs帽。在下界面处形成的2DEG的电性质（即，其迁移率和片密度）的测量由于掺杂帽层和Al= Gal-1-Jks层中同时导电的存在而变得复杂。对这种生长结构的简单霍尔测量的结果产生的参数是整个结构的平均值，并且不指示2DEG本身的质量。
We have tested the degree to which an analysis of the magnetic field dependence of the resistivity and Hall coefficient of HEMT structures can yield reliable values of sheet density and mobility of the 2DEG in the presence of parallel conduction. We find that this procedure works quite well at 77 K even for low, commonly obtained magnetic fields up to 5 kG. The analysis is simple and useful for routine characterization, and it obviates the need for tedious etch removal of the conducting cap and A1GaAs layers.High electron mobility transistor structures (HEMTs) make use of the ability to grow atomically abrupt interfaces to form a highly mobile two-dimensional electron gas (2DEG) at the interface of two semiconductors with different bandgaps. The prototypical structure is comprised of a layer of Si-doped AlxGal-xAs grown on undoped GaAs, with a highly doped GaAs cap on top. Measurement of the electrical properties of the 2DEG which forms at the lower interface, ie, its mobility and sheet density, is complicated by the presence of simultaneous conduction in the doped cap and Al= Gal_~ Jks layers. The results of a simple Hall measurement on such an as-grown structure yield parameters that are an average over the entire structure, and do not indicate the quality of the 2DEG itself.