Key Technologies For Ge-based Optical Interconnection

With the continuous improvement of the level of semiconductor technology,integrated scale and circuit speed increase rapidly,resulting in a series of electrical interconnection problems.In order to solve these problems,optical interconnect technology is proposed.Ge can be changed from indirect bandgap semiconductors to quasi-direct bandgap or direct bandgap semiconductors by application of modification techniques?such as stress?,so the carrier radiation recombination efficiency of modified Ge is high,which can be used in optical devices.The mobility of Ge semiconductor carriers is higher than that of Si semiconductor carriers,so Ge device can work fast and have good frequency characteristics in electronic devices.In view of the application advantages of modified Ge semiconductors in both optical devices and electrical devices,it has been the potential material of monolithic optoelectronic integration and became a hotspot and focus in this field.Based on the Schrodinger equation,for the modified Ge semiconductors,the strain tensor and deformation potential model are studied and built.The kp perturbation method is used to establish the modified Ge material conduction band,the valence band E-k relation model and kp model of the direct bandgap Ge_1-xSn_x alloy,which provides important theoretical basis for the study of the subsequent bandgap type conversion,modified Ge energy band structure and modulation.Based on the modified Ge strain tensor model and the deformation potential model,the modified Ge bandgap type transformation model under different modification conditions are established,and the conversion laws of the modified Ge bandgap type are revealed.Based on the E-k relationship model of the modified Ge material conduction band and valence band,the band structure model of direct band gap relaxation Ge_1-xSn_x alloy and quasi-direct bandgap modified Ge semiconductor are established.And those provide important theory for the design of active layer of light emitting device in subsequent Ge-based optical interconnection.According to the active layer energy band relationship requirements of each device of the same layer single-chip optoelectronic integration,based on the theory of solid band energy,the variation law of band gap width is studied under the action of uniaxial stress in the case of direct band gap relaxation Ge_1-xSn_x alloy and quasi-direct bandgap.And the bandgap width modulation scheme of the modified Ge under the uniaxial stress is proposed,which provides an important theoretical reference for the realization of Ge-based single-layer photoelectric integration.Based on the Sellmeier dispersion equation and the Lorentz-Lorenz equation,the refractive index model the direct band gap relaxation Ge_1-xSn_x alloy and the quasi-direct bandgap modified Ge semiconductor are established.On the basis of this,the FDTD simulation is used to optimize the geometric structure parameters of the modified Ge rectangular waveguide.In view of the compatibility of the waveguide and the light emitting device,the modified Ge tapered transition waveguide region is simulated and the relevant conclusions are obtained.In this paper,the modified Ge band E-k relationship model,energy band modulation and waveguide waveguide related research,will provide an important theoretical basis for the research and design of the active layer of the light emitting device in the Ge-based optical interconnection and the realization of the Ge-based single-layer photoelectric integration.