A measuring device and photoconductive analysis method for energy level distribution of surface traps

Abstract

The invention belongs to the field of trap energy level distribution measurement and provides a surface trap energy level distribution testing device and a photoconductive analysis method for realizing the measurement of the surface trap energy level distribution of a sample. The test device of the present invention includes a vacuum constant temperature chamber, a vacuum pump, a temperature control system, a solid-state laser, a digital voltage and current source meter and a computer; a constant preset voltage is applied to both ends of the sample to be tested through the digital voltage and current source meter, and the measured Dark current; then, start the photoconductivity test, and measure the photoelectric decay curve; finally calculate the trap energy level distribution on the surface of the sample according to the photoconductive decay curve. In the present invention, the constant temperature cavity provides a dark, constant temperature vacuum environment, which effectively avoids the interference of temperature, atmosphere and external light source during the whole measurement process, and greatly improves the measurement accuracy; at the same time, the photoconductivity curve obtained by using sub-gap laser excitation can be Accurately reflect the distribution of defects in the forbidden band, and exclude the influence of intrinsic defects.

Description

technical field [0001] The invention belongs to the field of trap energy level distribution measurement, in particular to a surface trap energy level distribution test device and a photoconductive analysis method. Background technique [0002] With the development of industrialization and the advancement of science and technology, transition metal oxide materials play a very important role in the semiconductor industry. The physical properties of the material are closely related to the surface structure. The change of the surface structure will inevitably lead to the change of the physical properties of the material. The introduction of defects on the surface of the material can significantly improve the physical properties of the material; and transition metal oxides have various structures and valence states. It has great tolerance for the introduction of defects, so it has become the main research object of surface modification. Ion implantation is a commonly used method...

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Problems solved by technology

For example, the publication number is: CN 104714165 B, and the invention title is: the photoconductive analysis method of interface trap energy level distribution discloses a photoconductive analysis method of interface trap energy level distribution. The invention is based on the Schottky structure. The test sample is irradiated with a laser with an energy greater than the forbidden band width, and the test in the atmospheric environment is suitable for the interface between two materials; however, the measurement of the trap energy level distribution on the surface of the material cannot be carried out in the atmospheric environment, because the sample The gas adsorption on the surface will affect the accuracy of the measurement; moreover, the single surface of the material cannot form a Schottky barrier contact, so that this method cannot accurately reflect the information of the sample surface and is no longer applicable

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