Study On The New Modes Of Heteroepitaxial Growth Of Ⅲ-Ⅴ Semiconductors

With the development of information technology,silicon-based VLSI technology with electronics as information carrier has been very mature and widely used.At the same time,the optical communication technology with high speed and large bandwidth,which takes photon as information carrier,has also developed rapidly.People are committed to combining the advantages of optoelectronic and microelectronic technology,integrating silicon based microelectronic devices and optoelectronic devices on the same chip,so as to realize optoelectronic integration.However,due to the large lattice mismatch,thermal mismatch and polarity mismatch between silicon and Ⅲ-Ⅴ semiconductor materials,the quality of Ⅲ-Ⅴ semiconductor materials grown on silicon substrates is difficult to meet the needs of high-performance device preparation.Therefore,it is very necessary to study the heteroepitaxial growth mode of semiconductor.Our research group found that the previous theory of crystal heteroepitaxial growth mode is not perfect,such as the lack of basis to treat the growth mode under tensile strain and compressive strain as equivalent,and the division of various growth mode regions is not accurate enough.Therefore,this dissertation work around the national key research projects and the Beijing municipal science and technology plan project mission requirements,based on professor Ren Xiaomin’s qualitative and quantitative revision of growth model theory,in order to further supplement and improve the theory of growth mode,the surface energy of related materials and interface were calculated,and the characteristics of heterogeneous epitaxial growth model under the strain were explored through the experiment.The main research contents and achievements are as follows:1.In order to determine the surface energy dominance of semiconductor heteroepitaxial growth material combinations,on the basis of previous related work,the calculation methods of material surface energy and interface energy are summarized.The surface energy of common Ⅲ-Ⅴ group semiconductor compounds such as AlAs and AlSb and the interface energy between InP and GaAs,InAs and GaAs materials were calculated for the first time.Some results were compared with the values given in other literatures,and the errors were found to be within the ideal range.The surface energy and interface energy values were used as the basis for subsequent experiments.2.In view of the problem that the growth modes under tensile strain and compressive strain were regarded as equivalent in the original growth mode theory,according to the prediction made by our research group about the existence of reversal modes under tensile strain,the characteristics of heteroepitaxial growth reversal modes were studied.We chose the GaAs/InP material combination,in which the lattice constant of the epitaxial layer is smaller than that of the substrate（the epitaxial layer is subject to tensile strain）,and the corresponding surface energy dominance is positive,which can be located in the second quadrant of the growth mode zoning diagram.The experimental scheme is to use molecular beam epitaxy（MBE）technology,with（100）InP as the substrate,GaAs material epitaxy growth.The irregular surface structure of the pupal bulge was observed.The average height of the bulge was 2～3nm,the width was 20～30nm,and the length was 100～200nm.The surface roughness of the samples was 1.22nm.The dislocation density is 10¹³/cm².Finally,we come to the conclusion that this growth characteristic belongs to VW growth mode under tensile strain,namely reverse VW mode.The existence of the reversal mode is verified experimentally for the first time.3.GaAs epitaxial layers were grown on InP substrates by the two-step method.The surface roughness of the samples was more than 3nm,the FWHM of PL spectra was 618.6 arcsec,and the dislocation density was 1.2×10⁹/cm²,the crystal quality of the material is still very poor,indicating that the two-step method does not significantly improve the crystal quality of the sample.The analysis shows that under the experimental conditions set in this study,the epitaxial GaAs on InP substrate may correspond to the depth reversal VW mode.