ZHENG Feihu, ZHANG Yewen. Progress in Research on Space Charge Distribution Measurements in Solid Dielectric Thin Films[J]. 2020, 46(7): 2460-2470.DOI:
Dielectrics films are widely used as insulating materials and functional materials
and the distribution of space charge is their important feature parameters under high voltage application. As functional dielectric films
the space charge distribution can affect the external characteristics of the functional devices. In this paper
we summarize the research progress of non-destructive measurement of space charge distribution in dielectrics films with the thickness of several nanometers to dozens of micrometers. According to the achieving spatial resolution of the measuring technologies
we introduce
respectively
the measurement methods including pressure wave propagation method
thermal perturbation method
electro-acoustic reflection method
femtosecond pulse laser based high space resolution measurements
and the related data processing algorithms. The characteristics of these measurement methods are compared
and several key factors affecting the measurement resolution are discussed as follows: the disturbance mode to the dielectrics films
the detection mode to the dielectric response signal
and the deconvolution method for the response signal processing. Pressure wave method and thermal disturbance method are relative mature and effective measurement method
of which their resolutions are between sub-micron and several microns. The disturbance and the response signal monitoring are relatively easy to achieve. The thermal disturbance method is easier to achieve sub-micron resolution
but the data processing is more tedious. The measurement of electro-acoustic reflection method is based on network analyzer and has micrometer spatial resolution. The photoelectric measurement method based on femtosecond pulse laser disturbance is considered to be an improvement of the traditional pressure wave method or pulsed electro-acoustic method. The ultra-high bandwidth measurement is realized by means of THz pulse disturbance
and the spatial resolution of tens of nanometers has been achieved.