Grating coupling type Ge series near-infrared waveguide detector and preparation method thereof

Abstract

The invention provides a grating coupling type Ge series near-infrared waveguide detector and a preparation method thereof. A Si layer and a SiO2 layer are enabled to form a Bragg reflector structure by growing the Si layer and the SiO2 layer to improve the coupling efficiency, and a focusing type non-uniform grating structure is formed by etching a P-type Si material layer. A thin Ge material buffer layer with the doping concentration lower than that of a P-type Si material layer is grown between the P-type Si material layer and a GeSn alloy material, the influence of lattice mismatch is reduced, optical loss generated by auger recombination is reduced, the length of a light absorption layer can be reduced through the generated intrinsic Ge0.94Sn0.06 material layer, and the optical detection range can be expanded to be longer. Therefore, the grating coupling type Ge near-infrared waveguide detector not only can solve the problems of low coupling efficiency, low light response and the like of a traditional detector, but also can meet near-infrared spectrum detection, has the characteristics of high speed, high response and easiness in integration with a silicon substrate, and has relatively high photoelectric conversion efficiency and light stability.

Description

technical field [0001] The invention belongs to the technical field of semiconductor optoelectronics, and in particular relates to a grating-coupled Ge-based near-infrared waveguide detector and a preparation method thereof. Background technique [0002] Photodetector is one of Si-based photoelectric active devices, and it is a key module in many application fields. According to the absorption characteristics of different materials for different wavelength bands, the device can realize the detection of light from ultraviolet, visible to infrared. Among them, the near-infrared photodetector in the 1100-2500nm band has a stronger ability to penetrate dense fog and a large amount of dust in the atmosphere than visible light, and can achieve low-loss resolution compared to mid-infrared and far-infrared objects without background objects It has applications in biological sensing and pattern recognition, night vision imaging, atmospheric remote sensing, optical fiber communication...

AI Technical Summary

Problems solved by technology

[0008] In the prior art, the focus of research on optical detectors is mainly focused on the improvement of the performance of a single device, but for waveguide detectors, the light source is emitted from the optical fiber to the waveguide, propagates through the waveguide, and finally enters the Ge detector. There is a large propagation loss

[0009] The existing technology cannot effectively reduce this part of the propagation loss when facing Si-based optoelectronic integration applications, making the coupling efficiency from the waveguide to the detector low

Moreover, the low near-infrared absorption and high surface recombination of the GeSn alloy material active layer lead to problems such as low photodetection efficiency, excessive dark current, narrow bandwidth and slow response speed of the photodetector.

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