Study On Crystallization Of Si,Ge And Multilayer Films By Ion Beam Sputtering

Si and Ge are the most important and popular semiconductor materials in the field of microelectronics and optoelectronics,not only have the high carrier mobility and conductivity,the energy band structure of low-dimensional system materials can also be realized by indirect bandgap to Quasi-direct bandgap,which greatly improve the luminous efficiency,more importantly,can be compatible with the existing mature Si planar technology.In this paper,the ion beam sputtering method was used to grow the samples.The crystallinity of Si and Ge monofilms epitaxially grown on Si substrate,induction and inhibition of heterogeneous growth of GeSi nanofilms on the buffer layer,the crystallinity and interface structure of Ge/Si multilayer films were studied respectively.Mainly carried out the following work:1.The Si films were homogeneous epitaxial grown on Si(100)substrate by ion beam sputtering.The effect of substrate temperature on the crystal quality of the film was studied.The results show that the epitaxial Si films are changed from amorphous Si(a-Si)to crystalline Si(c-Si)with the increase of substrate temperature.The crystallization temperature of Si film is 831 K.At the crystallization temperature,Si film is a microcrystalline Si(?c-Si)structure in which c-Si and a-Si are mixed,the crystallization rate is 59%,and the crystal grain size is large.The crystal quality of Si film was characterized by Raman.The results show that the Si grain size increased first and then decreased with the increase of substrate temperature.2.The Ge films were heteroepitaxially grown on Si(100)substrate by ion beam sputtering.The effect of substrate temperature on the crystal quality of the film was studied.The results show that the epitaxial Ge film are changed from amorphous Ge(a-Ge)to crystalline Ge(c-Ge)with the increase of substrate temperature,and the crystallization temperature of Ge film is 558 K.At the crystallization temperature,the crystallization rate of the film was 85.9%.When the temperature was increased to 624 K,the crystallization rate was 98.8%and the film preferential growth along the(200)crystal face.Continue to increase the temperature to 705 K,the film strict epitaxial growth along the(400)crystal face.With the increase of substrate temperature,the grain size of Ge firstly increases and then decreases,and the Raman peak decreases first and then increases.3.Ge/c-Si/Si,Si/c-Ge/Si,Si/a-Ge/Si heterogeneous Ge and Si monofilms with a buffer layer were grown by ion beam sputtering.The influence of the crystallinity of the buffer layer on the crystallization of epitaxial growth of Si and Ge films was studied.The results show that compared with the crystallization of the Ge and Si films grown directly on the Si substrate,the Ge films have a Si buffer layer were not easily crystallized,and the Si films have a Ge buffer layer were more easily crystallized.The better the crystallinity of the buffer layer,the upper heterogeneous films are easier to crystallize.4.Ge/Si multilayer films were grown on crystalline Si buffer layer by ion beam sputtering.The effect of substrate temperature on the crystallinity and interfacial structure of Ge/Si multilayer films was studied.The results show that when the substrate temperature is too low,the energy of the deposited atoms is small,the diffusion is insufficient and the crystallinity of the films is poor,but the interface of each sublayer is clear and the surface is flat.The high temperature will cause the multilayer interface mix serious and film quality become poor.Only by choosing appropriate growth temperature of film crystallinity and interface structure in an optimal state.