Femtosecond laser ablation-based infrared-enhanced Si-PIN detector and preparation method thereof

Abstract

The invention provides a femtosecond laser ablation-based infrared-enhanced Si-PIN detector and a preparation method thereof. The detector comprises an intrinsic silicon substrate, a femtosecond laser ablation microstructure layer, an infrared-enhanced amorphous silicon-ruthenium alloy film, a lower electrode, a P-type region, an annular P+ type region and an upper electrode, wherein the femtosecond laser ablation microstructure layer is a micron sharp cone array. The unabsorbed light which transmits through a space charge region is reflected for multiple times; a light propagation path and the photo capture ratio are increased; absorption and utilization of the light are improved; more photo-induced carriers are excited; the responsivity of the detector is improved; a relatively narrow optical band gap is obtained through controlling the ruthenium content; and the band gap of a silicon material is narrowed, so that near-infrared light with lower energy and a larger wavelength is captured; absorption of the near-infrared light can be additionally increased; and the detection spectrum range of a photoelectric detector is expanded.

Description

technical field [0001] The invention belongs to the technical field of photodetectors, relates to a photodetector structure, in particular to a femtosecond laser ablation infrared enhanced Si-PIN detector and a preparation method thereof. Background technique [0002] As an important part of optical fiber communication system, infrared imaging system, laser warning system and laser ranging system, photoelectric detectors have been widely used in civilian and military applications. Currently widely used photodetectors mainly include silicon photodetectors for detecting wavelengths from 400nm to 1100nm and InGaAs near-infrared photodetectors for detecting wavelengths greater than 1100nm. Among them, Si-PIN photodetector has the characteristics of fast response speed and high sensitivity, and its raw material Si is rich in resources, low in cost, easy to large-scale integration, and related technologies are mature, so silicon-based detectors are widely used. However, due to th...

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Problems solved by technology

However, due to the relatively large refractive index of Si, the reflection loss of incident light on its surface is large, reaching more than 30%, and its forbidden band width is large (1.12eV), which cannot absorb light greater than 1100nm, that is, it cannot detect light greater than 1100nm. The optical signal of the wavelength is generally replaced by an InGaAs photodetector at this time

However, InGaAs materials are very expensive, have poor thermomechanical properties, poor crystal quality, and are not easily compatible with existing silicon microelectronics processes, and there are many disadvantages

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