A silicon-based detector with gradually changing width and its preparation method

Abstract

The invention discloses a silicon-based detector with gradually changing width, comprising: SOI substrate, including: a bottom silicon material layer, a silicon dioxide buried layer, a top layer of silicon, and a waveguide layer is formed on the top layer of silicon; an n-type lightly doped region , formed on the waveguide layer; the n-type heavily doped region, formed on both sides of the n-type lightly doped region; the light absorbing layer, formed on the n-type lightly doped region, part of the upper surface of the light absorbing layer is formed with light The p-type heavily doped region of the absorbing layer; the silicon dioxide window layer is formed on the top layer of silicon and the waveguide layer, and an epitaxial window is opened on the silicon dioxide window layer corresponding to the waveguide layer; the two corresponding to the n-type heavily doped region A first electrode window is opened on the silicon oxide window layer and the insulating medium layer; a second electrode window is opened on the insulating medium layer corresponding to the p-type heavily doped region of the light absorbing layer; an n electrode is formed on the first electrode window; The p-electrode is formed on the second electrode window; the width of the light absorbing layer near the light-incident end is greater than the width away from the light-incident end.

Description

technical field [0001] The invention relates to the field of optical interconnection, in particular to a silicon-based detector with gradually changing width and a preparation method thereof. Background technique [0002] High-frequency photonic links have the advantages of wide bandwidth, low transmission loss, small size, low weight, and strong anti-electromagnetic interference capabilities, which can effectively improve the transmission capacity and transmission rate of communication systems, and are widely favored in many microwave and millimeter wave applications , such as microwave photon radar, phased array antenna and ROF (radio-on-optical communication), etc. Low dark current, high speed, high responsivity and high saturation power photodetectors are crucial in RF (radio frequency) photonic links. Due to the limitation of the bandgap width of the silicon material, the working wavelength of the silicon detector is below 1100nm, which is not suitable for light detect...

AI Technical Summary

Problems solved by technology

The first method needs to use an on-chip waveguide optical splitter for light splitting. The processing accuracy of the on-chip waveguide optical splitter is relatively high, the overall size of the device is relatively large, and the optical splitter itself has a certain amount of optical loss, resulting in The responsivity is low (Optics Express, 23(2015) 22857 22866.); the main problem of the second method is that although the side waveguide can homogenize the light field intensity in the detector, it is difficult to meet the effective light absorption length at the same time , so the photoresponsivity is also relatively low

The lateral waveguide occupies the lower electrode area of ​​the detector, resulting in a large series resistance of the device and limited bandwidth (Optics Letter, 42(2017) 851854.)

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