Surface plasma effect based InGaAs optical detector allowing absorption enhancement

Abstract

The invention provides a surface plasma effect based InGaAs optical detector allowing absorption enhancement. The surface plasma effect based InGaAs optical detector allowing absorption enhancement comprises a semiconductor substrate and a buffer layer, a lower doping layer, an absorption layer and an upper doping layer which are sequentially deposited on the semiconductor substrate and a metal grating layer which is formed in the upper doping layer; the metal grating layer is the two-dimensional periodical sub-wavelength optical grating; incident optical waves enters into from one semiconductor side with no thin film deposited on; two electrodes of the InGaAs infrared optical detector are connected electrically with the lower doping layer and the upper doping layer; additional bias voltage is introduced through the two electrodes; detected signals are collected through the two electrodes. According to the surface plasma effect based InGaAs optical detector allowing absorption enhancement, a two-dimensional periodical metal hole array structure can be in coupling with detected optical waves to simulate the surface plasma effect, the surface plasma effect can localize light fields at positions close to metal and semiconductor interfaces, and the lost detection rate of the thinned absorbing layer is recovered.

Description

technical field [0001] The invention relates to the technical field of photodetectors, in particular to an InGaAs photodetector with enhanced absorption based on the surface plasmon effect. Background technique [0002] Infrared detectors are the core components of infrared systems and thermal imaging systems, and InGaAs material is an excellent near-infrared photoelectric detection material. In the field of near-infrared detection, the material systems that can be applied in the 1-3 micron band are mainly based on mercury cadmium telluride (HgCdTe), indium antimonide (InSb) and indium gallium arsenide (InGaAs). InGaAs detectors have the characteristics of stable system and low refrigeration requirements. [0003] The InGaAs detector has a higher detection rate at a higher operating temperature, a higher signal-to-noise ratio, lower power consumption and a longer life, and is conducive to the miniaturization of the system; at the same time, the InGaAs epitaxial material has...

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Problems solved by technology

[0005] In the process of realizing the present invention, the applicant found that the prior art InGaAs infrared photodetector has the following technical defects: due to the thickness of the existing detector structure absorbing layer is relatively thick, the generation and recombination current of carriers is relatively large, which becomes One of the main sources of dark current; at the same time, the thickness of the thicker absorbing layer will increase the transit time of carriers, resulting in slower response speed of the device; for the flat metal structure, it can only play a reflective role. The effect increases the propagation length of light; while the use of a one-dimensional periodic grating structure will improve the absorption enhancement to a certain extent, but it will have a strong selectivity for the polarization direction of light

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