【摘要】 本文基于扫描探针显微镜(SPM)建立了微区电容的低频测量系统,最小测量电容为30aF,工作频率为20～100kHz。试验测量了SPM导电针尖与金属样品之间的电容Ctip与它们之间的距离z关系曲线,并同时通过光学系统测量了针尖的关于频率的一次受力信号Fw与z的关系曲线。推导了两种测量方法所获曲线的内在关系,并获得了针尖与样品的表面势之差。并且,利用此系统测量了Al0.3Ga0.7N/GaN薄膜的微区C-V曲线,获得和宏观C-V曲线趋势一致的结果。更多还原

【Abstract】 It’s present in the paper that a system measuring micro-area capacitance with a low frequency method is established on the scanning probe microscopy(SPM).The smallest capacitance measured is 30 aF,and the system can work between 20 to 100 kHz.A curve of the capacitance Ctip between the AFM tip and metal depending on their distance z is measured,and at the same time,so do with a curve of the first-order force single Fw of frequency depending on z.We confirm the relationship of the two curves with different method after a comparison,and calculate out the difference of the surface potential between the tip and sample.At the last,we get the micro-area C-V curve of Al0.3Ga0.7N/GaN thin film.It has the same trend with the macroscopic C-V curve.更多还原