Avalanche photo-diode based on AlInAsSb body material as multiplication region and preparation method therefor

Abstract

The invention provides an avalanche photodiode based on AlInAsSb body material as the multiplication region, comprising: a substrate; a buffer layer epitaxially on the substrate; an N-type ohmic contact layer epitaxially on the buffer layer and having a cross section of "" Convex" shape, its lower half is consistent with the shape of the substrate, and its upper half is cylindrical; the avalanche multiplication layer is epitaxial on the upper surface of the upper half of the N-type ohmic contact layer, composed of AlxIn1‑xAsySb1‑y Bulk material preparation, the doping concentration is less than 1016cm-3, the value range of x is: 0≤x≤1, the value range of y is: 0.08≤y≤1; the P-type charge layer is epitaxial on the avalanche multiplication layer ; The light absorbing layer is epitaxial on the P-type charge layer; and the P-type ohmic contact layer is epitaxially on the light absorbing layer. The avalanche photodiode has the advantages of low noise and high gain-bandwidth product, and at the same time effectively reduces the dark current, which not only meets the requirement of high sensitivity of the photodetector, but also realizes the design of energy band engineering and broadens its application range.

Description

technical field [0001] The invention belongs to the field of semiconductor devices, in particular to an avalanche photodiode based on an AlInAsSb bulk material as a multiplication region and a preparation method thereof. Background technique [0002] Photoelectric detectors have a wide range of uses in various fields of military and national economy. They are mainly used for ray measurement and detection, industrial automatic control, photometry, etc. in the visible or near-infrared band; they are mainly used in missile guidance and infrared thermal imaging in the infrared band. , infrared remote sensing, etc. In recent years, due to the rapid development of optical communication systems, the requirements for receiver responsivity and response speed are getting higher and higher, and higher requirements are also put forward for the sensitivity of photodetectors. [0003] Among the existing photodetectors, the PIN photodiode has the advantages of simple structure, easy manuf...

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Problems solved by technology

[0003] Among the existing photodetectors, the PIN photodiode has the advantages of simple structure, easy manufacturing process, high reverse bias voltage, and wide linear output range. Its typical device silicon PIN large-area photodetector is widely used in laser detection system, fast pulse detector, etc., but because the intrinsic I-layer resistance of the PIN photodiode is large and the output current is small, its detection sensitivity is relatively low when detecting weak light, and it is necessary to pre-amplify the signal. This makes the detection sensitivity limited by the thermal noise of the external amplifier, shortens the relay distance of the communication system, increases the number of relay stations required, and increases the operating cost of the entire system; and the avalanche photodiode (Avalanche Photo- diode, APD) can provide 5dB~10dB higher sensitivity than PIN photodiodes, and has a greater advantage in weak light detection than PIN photodiodes

[0004] However, in view of the current demand for high sensitivity of photodetectors, the existing avalanche photodiode APD still needs to further improve its detection sensitivity

The avalanche photodiode APD has high sensitivity due to its internal gain, but at the same time, the randomness of its gain will be accompanied by additional noise, and the traditional APD uses Si, InP, InAlAs and other materials as the multiplication region, and there is a gain-bandwidth Product limitation, that is, when the gain is high, the bandwidth will decrease due to the increase of the avalanche settling time, thus limiting the response speed of the receiver. Therefore, it is necessary to propose a low noise, high gain-bandwidth product, low dark current, and high response APD to meet the high sensitivity needs of photodetectors

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