Study On Si-based Modified Ge Infrared Luminescent Devices

Since the 1970 s,microelectronic integrated circuits have developed rapidly and the integration density has followed Moore's Law.As the size of integrated circuits continues to shrink,the physical limits of microelectronic integrated circuits are about to be touched.Due to the high heat generation and quantum effect caused by the high integration density,the development of today's integrated circuits encounters bottlenecks.For compatibility with current CMOS processes,the most viable solution to these problems is the use of Si-based optical interconnect technology.In the Si-based optical interconnection circuit,the existing scientific research level has well solved the preparation of other photoelectric devices,but the Si-based light source is still in the research stage because of its own particularity.Therefore,it is of great significance to study Si-based light sources.Based on the IV Ge material,the luminescent properties of modified Ge materials are analyzed in detail.Firstly,based on the Van de Walle deformation potential theory,the energy band structure of the modified Ge material and the distribution of carriers in its conduction band are calculated.Secondly,the radiative recombination of carrier in the direct band gap,indirect band gap and the competitive relationship of Auger complex are analyzed.Based on this,the internal quantum efficiency and optical gain of N-doped tensile strained Ge materials are calculated.Under the condition of tensile strain of 1.75%,the calculated internal quantum efficiency of the N-doped Ge material can reach 89.2%.The calculation of the optical gain shows that the modified Ge material is comparable to the III-V material.It can be seen that the tensile strain effectively enhances the direct bandgap transition luminescence of Ge materials.This article also briefly analyzes the advantages of the newly emerging Group IV material Ge Sn alloy.However,the preparation of high-content Ge Sn materials and devices still pose great challenges due to segregation of Sn components,lattice mismatch,and thermal stability.This paper analyzes the advantages of heterojunctions,PIN junctions,silicon nitride stress films and other applications in optoelectronic devices,and combines these advantages to design a vertical structure of Si-based modified Ge infrared light emitting diodes,and through Silvaco professional simulation software simulates the optoelectronic characteristics of the device.Among them,in this paper,for the simulation of the photoelectric characteristics of the Si-modified Ge infrared light emitting diodes,the P/N doping concentration,the thickness of the intrinsic Ge layer,the strain and the temperature are selected as the key parameters affecting the simulation.The relationship between device performances,such as J-V curve,P-I curve,and spectral response,are obtained by simulation.The simulation results show that the Si-modified Ge infrared light emitting diode has good luminescence properties.When the applied forward voltage is about 0.3V,Si-based modified Ge infrared light emitting diodes are all working properly.The amount of strain has the greatest influence on the performance of Si-based modified Ge infrared light emitting diodes.Therefore,the growth of silicon nitride films is particularly important,which is related to the amount of applied strain.The tensile strain applied to the silicon nitride film must reach a certain amount to change the energy band structure of Ge to convert it into a direct bandgap semiconductor material,effectively increase the luminous intensity and luminous efficiency to meet the requirements of practical applications.Increasing the thickness of the intrinsic Ge layer within a certain range is favorable for improving the photoelectric characteristics of the device.However,when the thickness exceeds a critical value,the photoelectric characteristics of the device decrease.Therefore,the device performance can be optimized only by choosing the proper thickness of the intrinsic Ge layer.At high temperature,the non-radiative recombination of the free carrier absorption with the material becomes more intensified.At too high temperature,the optical gain of the Ge material decreases instead.Therefore,it is also very important to select an appropriate working environment for the Si-modified Ge infrared light emitting diode.It is hoped that this paper will have guiding significance for the design of Si-based modified Ge infrared devices,and will provide an important theoretical basis for subsequent experiments on Si-based modified Ge infrared diodes.