Silicon On Chip Led Integration Technology And The Coupling With Waveguide

With the rapid development of microelectronic technology in the 21st century,integrated circuits are developing towards small and complex,which leads to the feature size almost reduced to the limit,and the performance improvement of integrated circuit chips in the era of"post Moore's law"is seriously restricted.Different from general integrated circuits,on-chip silicon light-emitting diode(LED)integrated circuits can not only complete the transmission of electrical signals on chip,but also realize the transmission of optical signals,which can alleviate the interference of electrical signals in high integration environment.In order to give full play to the rapid characteristics of optical signals,it is bound to vigorously develop new optoelectronic devices.Silicon avalanche light emitting diode(Si AMLED)shows many advantages such as good compatibility with traditional IC manufacturing process and low cost.It can be used as the basic light-emitting unit in the on-chip silicon LED integration technology.Breaking through the limitation of silicon indirect band gap and improving the luminous efficiency of silicon light source has always been the hotspot and difficulty in the design of silicon LED.In addition to the need for efficient and reliable silicon light source,the loss of light energy in the transmission process of on-chip system is also a key concern.In order to better adapt to all-silicon optoelectronic integration and realize a monolithic integrated on-chip optical interconnection system,the material of waveguide needs to be reasonably designed according to CMOS process and finally guarantee the low loss transmission of light signal in the whole system.Aiming at the on-chip silicon LED integration technology,starting from the luminous principle,performance index and design structure of silicon-based light-emitting devices,this thesis studies a light source using avalanche multiplication effect of silicon PN junction,and proposes a MOS-like Si AMLED device with three terminals based on the existing mature CMOS technology.The reverse biased PN junction in the device is composed of P⁺type active region and N-well,and the light-emitting window is close to both sides of the gate.The results show that positive voltage on gate is conducive to the concentration of light-emitting region from the inside to the surface area.The small-signal model put forward shows that the modulation frequency of the device can reach the level of GHz.After the Si AMLED is produced,the test shows that the threshold voltage is about-6 V and the wavelength range is 400 nm to 1100 nm.Under the influence of the third terminal,the threshold voltage can be reduced to-1.8 V,and the overall luminous intensity is improved.The power conversion efficiency is as high as5.98×10^-7.Considering that silicon nitride compatible with CMOS process has good optical transparency in the visible light above 600 nm,an optical waveguide coupling design based on silicon nitride is proposed.The simulation result shows that the energy loss in the optical waveguide is low.The transverse and longitudinal waveguide coupling modes are preliminarily explored,the causes of optical energy loss are analyzed,and the improvement scheme is briefly put forward.