Horizontal germanium detector structure and preparation method thereof

Abstract

The present invention discloses a horizontal germanium detector structure. The horizontal germanium detector structure is a horizontal photodiode structure and comprises a silicon substrate; a siliconoxide layer is deposited at the upper surface of the silicon substrate; the silicon oxide layer comprises top silicon, a first doped region is formed at one side of the top silicon, and a first electrode is formed at the upper surface of the first doped region; a coupling layer is formed at the upper surface of the top silicon, an extension portion is formed at one side, back to the first electrode, of the coupling layer, a second doped area is formed by the extension portion, and a second electrode is formed at the second doped area; and the silicon nitride waveguide is a taper structure andis formed at the upper portion of a polycrystalline silicon layer. Through reconstruction of the germanium layer structure, the top silicon and the germanium layer are doped to enhance the coupling efficiency of the silicon nitride waveguide being coupled to the germanium detector so as to achieve the effective integration of an optical multiplexer, an optical demultiplexer and the germanium detector, and the horizontal germanium detector structure and the preparation method thereof are applied to the photoelectric detection field with high luminous power and high bandwidth.

Description

technical field [0001] The invention relates to the technical field of optical devices, in particular to a structure and a preparation method of a lateral germanium detector. Background technique [0002] Optical multiplexer (mux) and optical demultiplexer (demux) are one of the very important optical devices in optoelectronic chips at present. Considering the stability of optical multiplexer or optical demultiplexer, such as being affected by temperature and process The central wavelength of the optical multiplexer and the optical demultiplexer shifts and the spectral curve deforms due to the conditions. We need to select suitable materials to prepare the optical multiplexer and the optical demultiplexer. Since the refractive index of silicon nitride (SiN) and silicon oxynitride (SiON) is much less affected by temperature changes than silicon (Si) materials, so the optical multiplexer and optical demultiplexer choose SiN or SiON as the material, in practice In the applicat...

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Problems solved by technology

Since the refractive index of silicon nitride (SiN) and silicon oxynitride (SiON) is much less affected by temperature changes than silicon (Si) materials, so the optical multiplexer and optical demultiplexer choose SiN or SiON as the material, in practice In the application, the ends of the optical multiplexer and optical demultiplexer will be connected with the detector (PD) to realize photoelectric conversion. In ordinary optical module products, the optical multiplexer, optical demultiplexer and detector are in two separate Each chip is connected by optical fiber (fiber), which further increases the size and area of ​​the product and increases the complexity of the back-end optical process. Germanium (Ge) detector, the light is coupled into the Ge detector by the Si waveguide, the Ge detector structure is usually a vertical PIN structure, and this detector structure is not suitable for the application scene of this patent, and secondly, for the traditional CMOS process Ge detectors have relatively small saturation photocurrents, so they cannot be used for high optical power detection

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