A Method of Using Scanning Probe to Probe the Dielectric Constant of Materials

Abstract

The invention discloses a method for detecting the dielectric constant of a material by using a scanning probe microscopic technique. The invention comprises the following steps: firstly, the electric field gradient detection of the electrostatic force microscope is used to obtain the experimental value of the capacitance gradient between the probe and the sample; and then the theory of the change of the capacitance between the probe and the sample with the dielectric constant of the sample is established by using the image charge method model; finally, the experimental values ​​are compared with the theoretical model to deduce the dielectric constant of the sample. The invention can obtain the dielectric constant information of the sample at the nanometer scale, has the advantage of non-damage detection, and is suitable for the characterization of various dielectric materials such as insulators or semiconductors.

Description

technical field [0001] The invention relates to a method for detecting the dielectric constant of a material by using a scanning probe. Background technique [0002] In the prior art, the dielectric constant is an important inherent property of the dielectric material. Generally speaking, the relative dielectric constant (referred to as the dielectric constant) of the metal is very large, and the better the insulating performance of the dielectric, the smaller the dielectric constant. An extreme case is: the dielectric constant of an ideal conductor is infinite, and the dielectric constant of a vacuum is 1; at present, the conventional means of measuring the dielectric constant is mainly an optical ellipsometer, which is obtained by analyzing the interference of incident light in the thin film material. The complex refractive index, extinction coefficient, and permittivity of the ellipsometry are very similar; usually, the spot size of an ellipsometer needs to be at least te...

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Problems solved by technology

[0002] In the prior art, the dielectric constant is an important inherent property of dielectric materials. Generally speaking, the relative permittivity of metals (referred to as dielectric constant) is very large, and the better the dielectric insulation performance, the smaller the dielectric constant. An extreme case is: the dielectric constant of an ideal conductor is infinite, and the dielectric constant of a vacuum is 1; at present, the conventional means of measuring the dielectric constant is mainly an optical ellipsometer. complex refractive index, extinction coefficient, and dielectric constant; usually, the spot size of an ellipsometer requires at least tens of microns, so it is difficult to scan and analyze materials at the nanometer scale; with the development of semiconductor integrated circuits, microelectronic and optoelectronic materials The characteristic size of the device has entered the submicron or even nanometer level, and the analysis of the dielectric properties of these micro-nano electronic devices requires the introduction of new methods; on the other hand, since the atomic force microscope was invented in the late 1980s, Scanning probe microscopy has experienced vigorous development, and various extended modes—such as Kelvin mode, electrostatic force mode, conductive mode, magnetic force mode, piezoelectric force mode—have been developed and widely used in the surface analysis of micro-nano electronic materials Among them; the present invention is based on electrostatic force microscope technology, proposes a kind of new method that utilizes scanning probe to detect the permittivity of dielectric materials such as semiconductors at the nanometer scale

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