A kind of photodetector and preparation method thereof

Abstract

The invention provides a photoelectric detector, which comprises a semi-insulating InP substrate, an InP buffer layer, an InGaAs photosensitive layer, an InP cap layer and a passivation layer in laminated arrangement, wherein a through hole exposing the partial region of the InP cap layer part is formed in the passivation layer, an annular second electrode is formed along the inner side wall of the through hole, and the partial region of the second electrode extends to the upper part of the passivation layer for forming a lap joint region; the upper part of the lap joint region is directly provided with an electrode lead wire; a channel penetrating through the InP buffer layer, the InGaAs photosensitive layer and the InP cap layer is formed in the direction along any one tangent line of one side, near the contact region, of the through hole, and divides the InP buffer layer, the InGaAs photosensitive layer and the InP cap layer into two parts in a direction along the parallel surface of the InP substrate. Therefore the electrode lead wire cannot form a capacitor structure with each semiconductor layer, arranged vertically under the electrode lead wire, of the electrode lead wire, or even if the capacitor structure is formed, the capacitor structure cannot be connected into a photoelectric detector circuit, the parasitic capacitance formed by the electrode lead wire is effectively reduced, and the response speed of the photoelectric detector is accelerated.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to an indium gallium arsenic photodetector and a preparation method thereof. Background technique [0002] Photodetectors are semiconductor devices that convert optical signals into electrical signals, and are used in optical fiber communications, computer networks, cable TV networks, and various photoelectric control and photodetection systems. Among them, the PIN photodetector is suitable for working under low voltage, has high responsivity, good signal-to-noise ratio, and is easy to use. It is the most commonly used photodetector in optical communications at home and abroad. [0003] Usually, the PIN type photodetector usually adopts InGaAs material, and the structure of the PIN type InGaAs photodetector in the prior art is as follows: figure 1 As shown, it includes a semi-insulating InP substrate 1, an InP buffer layer 2, an InGaAs photosensitive layer 3, and an InP cap ...

AI Technical Summary

Problems solved by technology

[0005] For this reason, what the present invention is to solve is the problem that the existing PIN-type InGaAs photodetector has relatively large parasitic capacitance, which affects the response speed of the photodetector, thereby providing a high-speed InGaAs photodetector with small parasitic capacitance and its preparation method

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