| The rapid development of microelectronic technology has put forward higher requirements for the internal interconnection methods of integrated circuits.Electrical interconnection has gradually revealed disadvantages in terms of delay and other aspects,which make optical interconnection into everyone's sight.The optical interconnection uses a light source to convert an electrical signal into an optical signal,and transmits the optical signal to a photodetector through a certain coupling method.Then the optical signal is reduced to an electrical signal in the photodetector.Optical interconnection,which has the advantages of small delay and no interference between signals,is one of the best alternatives to traditional metal interconnection.The basic optical interconnection system consists of a light source,an optical waveguide,and a light detector.Although the III-V family light source design technology is relatively mature,its manufacturing process is complex,high cost,and difficult to be compatible with silicon integrated circuit manufacturing processes.We use silicon as a light-emitting material to realize an integrated light source.Not only has the advantage of being compatible with integrated circuit technology,but also reduces the update of production equipment.Therefore,manufacturing an integrated and efficient silicon light source has always been a hot and difficult point in the field of optical interconnection.This article mainly focuses on the monolithic integration technology of silicon light source.A light source,which utilizing avalanche multiplication process of PN junction,is studied in terms of the structure,mechanism and optoelectronic characteristics of monolithic integrated silicon-based light source.Based on the existing integrated circuit manufacturing process,a polycrystalline silicon avalanche-mode light-emitting device?P-SiAvLED?that can be integrated on a single chip is proposed in this paper.The light source is formed by stacking a silicon substrate,a silicon oxide layer,a polysilicon layer,and a silicon oxide protective layer from bottom to top.Both the active region and the light emitting region of the device are N+PN+PN+doped polysilicon layers.Starting from the device structure,we analyze its depletion region electric field and device capacitance,then establish a high-frequency small-signal model of the device.Subsequently,we tested and analyzed the optoelectronic characteristics of the device.Test data and calculation results show that the threshold voltage of P-SiAvLED is about 16 V.When the voltage is between 16 V to 30 V,it can emit orange-yellow light.The spectrum of P-SiAvLED is continuous,and the wavelength range covers 450 nm to 900 nm.When the current flowing through the device reaches40 mA,its luminous intensity can reach the order of microwatts,and the photoelectric conversion efficiency can reach the order of 10-6.The single-wavelength external quantum efficiency and power conversion efficiency have reached the order of 10-7 and10-8,respectively.The electroluminescence spectrum of the device has five light intensity peaks,and the peak positions are approximately 550 nm,580 nm,620 nm,680nm,and 770 nm.Spectral data shows that under the same driving current,the device is more inclined to emit photons with an energy of 1.8 eV?wavelength 680 nm?.We find that when the voltage across the device is between 24 V and 27 V,the current changes almost linearly with the voltage,and the light intensity of the device changes linearly with the driving current.Considering that the spectral responsivity of a silicon photodetector has a coincident band with P-SiAvLED,it can be concluded that it is a feasible idea that we use P-SiAvLED to form an optical interconnection system instead of traditional electrical interconnection in an all-silicon optoelectronic integrated circuit. |
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