Research On The Methods Of Compatible Heteroepitaxial Growth Of Semiconductor Materials

Since the advent of modern communication mode based on Shannon's information theory,people have been pursuing higher transmission rate,greater information capacity and higher communication quality.Therefore,the high speed,wide bandwidth and low loss optical communication technology as the information carrier has emerged and received more and more attention.Especially in recent years,Moore's law is almost invalid in the field of microelectronics technology.People have high hopes for the communication mode based on Photonics and related integration technology.Silicon based optoelectronic technology is a kind of frontier technology that makes optoelectronic devices and silicon-based microelectronic devices on the same chip to realize optoelectronic integration and meet the above development needs.As the best material for microelectronic devices,silicon has good electrical characteristics,and silicon-based passive devices and silicon-based detectors have good development.However,due to its poor luminous properties,high-efficiency silicon-based light source has become the most severe challenge for silicon-based optoelectronic integration.Based on this background,this paper focuses on the task requirements of the National Key Research and Development Program and Beijing Science and Technology Program,to realize the vision of silicon-based optoelectronic integration,and carries out the research on semiconductor compatible heterogeneous growth.The main research contents and achievements are as follows:1.Focused on the topic of mode-availability and mode-transition conditions for heteroepitaxial crystalline-growth,working together with my advisor,and based on the qualitative modification to the previous theory of heteroepitaxial crystalline-growth,the principle of heteroepitaxial mode divergence is proposed and then the corresponding quantitative modification is made,which makes the theory of heteroepitaxial crystalline-growth modes further complete.Meanwhile,the concept of the sub-modes of heteroepitaxial growth is put forward and the features of each sub-mode are clarified,thus having deepened the understanding of the truth about the mode evolution.In addition,the possibilities such as that of high quality growth of islands occurring in Volmer-Weber(VW)mode region is predicted.2.With the large mismatch InGaAs/GaAs epitaxial growth as the breakthrough point,the feasibility of "post S-K compatible-heterogeneous-growth mode" has been demonstrated by using single-layer quantum dot scheme,and phased progress has been made.The In0.78Ga0.22As target epitaxial layer/non-relaxing GaAs capping layer/InAs quantum dots/GaAs substrate epitaxial structure was grown by MBE technology.The effects of monolayer and growth temperature on the size and density of InAs/GaAs quantum dots were studied.The InAs quantum dots with density of 1011/cm2 were obtained at 480?.The optimization of monolayer was studied.Under the monolayer of 2.8ML,the diameter and height of the large quantum dots were about 50nm and 10nm respectively,and the diameter and height of small quantum dots were about 20nm and 3nm respectively.3.With the large mismatch InGaAs/GaAs epitaxial growth as the breakthrough point,the feasibility of "post S-K compatible-heterogeneous-growth mode" has been demonstrated by using multi-layer quantum dot scheme,and phased progress has been made.The In0.78Ga0.22As target epitaxial layer/(non-relaxing GaAs capping layer/In0.15Ga0.75As strain layer/InAs quantum dots)× 3/GaAs substrate substrate epitaxial structure was grown by MBE technology,and the density of the quantum dots is 1011/cm2.In0.15Ga0.75As strain layer was inserted between InAs quantum dot and non-relaxing GaAs covering layer which reduced the effect of local stress on the non-relaxing GaAs capping layer in InAs quantum dot region,thus reducing the probability of quantum dot array growth,realizing the staggered distribution growth among multi-layer quantum dots,and improving the overall uniformity of quantum fot distribution,so as to meet the requirements of "post S-K compatible-heterogeneous-growth mode".At the same time,the scheme of using this structure as a multi-layer quantum dot dislocation barrier layer to effectively reduce the threading dislocation density of heteroepitaxial growth.4.On the basis of previous research on optimization method of large-mismatched compatible hetero-epitaxial growth based on the relevance between dislocation density and mesa dimension in the laboratory,the correlation between the mesa dimension and the quality of GaAs/Si epitaxial layer is further studied.The experimental results show that the dislocation density of GaAs epitaxial layer grown by MOCVD and three-step method combined with cyclic annealing is not obviously dependent on the mesa linearity when the mesa dimension of Si substrate is greater than 50?m.When the mesa dimension of Si is respectively 50?m,10?m and 8 ?m,the dislocation density measured by ECCI is respectively 8.1 × 107/cm2,6.7×107/cm2 and 3.0×106/cm2,which means that the dislocation density of GaAs/Si epitaxial layer decreases with the decrease of mesa dimension within the range of the mesa dimension of Si substrate from 50?m to 8?m.At the same time,when the mesa dimension decreases from 50?m to 8?m,the PL peak value of GaAs/Si epitaxial layer is increasing,the linewidth is narrowing and the residual stress is decreasing.This work provides a new means of analysis and prediction for the improvement and optimization of the large mismatch hetero compatible epitaxial growth process.