Avalanche photodetector and preparation method thereof

Abstract

The invention provides an avalanche photodetector and a preparation method thereof. The avalanche photodetector comprises a substrate, the surface of which comprises a first semiconductor layer; the first semiconductor layer comprises a first P-type doped region, a second P-type doped region, a third N-type doped region, a first intrinsic region, a third P-type doped region, a second intrinsic region, a second N-type doped region and a first N-type doped region which are sequentially arranged in the first direction, and the dopant concentrations of the first P-type doped region, the second P-type doped region, the third P-type doped region, the third N-type doped region and the first N-type doped region are sequentially decreased. The dopant concentrations of the first to third N-type doped regions are sequentially decreased, and the first direction is an electron flow direction; the second semiconductor layer sequentially covers part of the second P-type doped region, the third N-type doped region, the first intrinsic region and the third P-type doped region in the first direction, and the first N-type doped region is connected with the first electrode; the third P-type doped region is connected with a second electrode; the first N-type doped region is connected with the third electrode.

Description

technical field [0001] The invention relates to the technical field of photon integrated chip detection, in particular to an avalanche photodetector and a preparation method thereof. Background technique [0002] As one of the core devices of the silicon photonics architecture, the avalanche photodetector has the function of converting low-power optical signals to electrical signals. The region is rapidly accelerated during the movement, and one or more collisions may occur during the movement, and secondary and three new hole-electron pairs are generated through the impact ionization effect, resulting in an avalanche multiplication effect, which rapidly increases the number of carriers, thus forming a comparative large optical signal current. [0003] At present, silicon germanium materials compatible with CMOS technology are widely used in silicon photonic integrated chips to realize avalanche photodetection. It uses silicon materials as optical waveguides and at the same...

AI Technical Summary

Problems solved by technology

At present, the disadvantages of the silicon-germanium avalanche photodetector structure are as follows: first, the epitaxial single-crystal silicon process is required, and the fabrication is relatively complicated; Reduce the quantum efficiency of the detector; the third is that the absorption region and the multiplication region are not easy to adjust independently, the concentration accuracy of the doping region is too high, the process tolerance is low, and the gain bandwidth is likely to be unsatisfactory

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