Lateral variations in threshold voltage of an AlxGa1−xN/GaN heterostructure field-effect transistor measured by scanning capacitance spectroscopy
Lateral variations in threshold voltage of an AlxGa1−xN/GaN heterostructure field-effect transistor measured by scanning capacitance spectroscopy
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DOI：
10.1063/1.1335840
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发表时间：
2001
影响因子：
4
通讯作者：
D. Schaadt;E. J. Miller;E. Yu;J. Redwing
中科院分区：
文献类型：
--
作者：
D. Schaadt;E. J. Miller;E. Yu;J. Redwing
在扫描电容显微镜（SCM）中进行的局部dC/dV光谱被用于以高空间分辨率（~ 50 nm）定量地绘制AlxGa 1 −xN/GaN异质结构场效应晶体管外延层结构的阈值电压的横向变化。扫描电容和相关联的阈值电压图像示出了直径小于150 nm的小圆形特征，阈值电压的相应偏移为约1.5-2 V，以及尺寸为几微米的较大特征，阈值电压的相应偏移为约1 V。SCM和阈值电压图像中的小特征与带电的穿透位错的存在一致，而在大面积上阈值电压的变化可能是AlxGa 1-xN层中的厚度和/或成分变化的结果。
Local dC/dV spectroscopy performed in a scanning capacitance microscope (SCM) was used to map, quantitatively and with high spatial resolution (∼50 nm), lateral variations in the threshold voltage of an AlxGa1−xN/GaN heterostructure field-effect transistor epitaxial layer structure. Scanning capacitance and the associated threshold voltage images show small round features less than 150 nm in diameter with a corresponding shift in threshold voltage of about 1.5–2 V, and larger features several microns in size with a corresponding shift in threshold voltage of approximately 1 V. The small features in the SCM and threshold voltage images are consistent with the presence of charged threading dislocations, while the variations in threshold voltage over large areas could be a result of thickness and/or composition variations in the AlxGa1−xN layer.