Avalanche photodiode and preparation method thereof

Abstract

The invention provides an avalanche photodiode applied to the technical field of photodetectors. A buffer layer, an absorption layer, a transition layer, a charge layer, a cap layer and an electrode contact layer are epitaxially grown on a substrate in order, the material of the electrode contact layer is InGaAsP, the electrode contact layer is an intrinsic gradual component material of epitaxialgrowth, the high concentration doping can be achieved by a P-type dopant diffusion doping process such as zinc diffusion, the upper surface doping concentration is 1019Atoms / cm3, and a P-type electrode is made of a non-alloy contact Ti-Pt-Au. The invention also discloses a preparation method of the avalanche photodiode, the high adhesion of Ti, the high toughness of Pt and the good electrical conductivity and corrosion resistance of Au are used, the ohmic contact characteristics of a device are effectively improved without affecting the dark current and frequency response of the device, the contact resistance is reduced, and the probability of fall is little.

Description

technical field [0001] The invention relates to the technical field of photodetectors, in particular to an avalanche photodiode and a preparation method. Background technique [0002] In the 21st century, with the development of semiconductor technology and technology, III-V photodiodes used in short-wave near-infrared will play an important role in optical communication industry, quantum security communication, quantum computing, space laser ranging, near-infrared high-resolution spectrometer and other industries. Important role of photoelectric conversion detectors. [0003] In current technology, alloy systems represented by Au-Be (gold beryllium) and Au-Zn-Pd (gold-zinc-lead) have good contact resistance, but because Be and Pd are toxic and some require solid phase regeneration (SPR, solid phase regrowth) ) process is complex, and the alloy process represented by the Au-Zn-Au (gold-zinc-gold) system, in which both Zn and Au have poor adhesion to the substrate, are easy ...

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Problems solved by technology

[0003] In current technology, alloy systems represented by Au-Be (gold beryllium) and Au-Zn-Pd (gold-zinc-lead) have good contact resistance, but because Be and Pd are toxic and some require solid phase regeneration (SPR, solid phase regrowth) ) process is complex, and the alloy process represented by the Au-Zn-Au (gold-zinc-gold) system, in which both Zn and Au have poor adhesion to the substrate, are easy to fall off, and have poor contact resistance, which affects the reliability of the process and the device. performance

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