Research On Growth Of AlN Films On The Si (111) Substrate

AIN is a wide band gap semiconductor material, and its band gap width is 6.2 eV. AIN has the characteristics of high breakdown voltage, high electron saturation drift velocity, and the strong ability to resist radiation. It has very bright developing prospects in the area of communication, electronic power, aerospace and etc. It is very common to use Si as substrate to grow AIN films, for it has better temperature conductivity, electrical conductivity and mechanical properties, and it is currently the most widely used semiconductor materials with crystalloid of high quality and maximal dimension. Since there is large lattice mismatch and thermal mismatch between the Si substrate and AIN/SiC, two-step growth method is generally taken for the growth of AIN materials. Similarly, when begins the epitaxial growth of SiC materials, the epitaxial growth on the Si substrate by AIN buffer layer could be firstly taken, and then starts the growth of SiC.This paper mainly discusses the following work:1, Using MOCVD method to grow AIN nucleation layer by epitaxial in the Si (111) substrate. Through a series experiments of Raman scattering spectrum, surface morphology SEM and AFM images, the result shows that the growth mode of AIN nucleation is the middle-growth which coexists 2-D Lateral growth and 3-D Longitudinal growth. And when the growth time 20 minutes, the thickness of the sample is 280 nm and the nucleation layer has the largest thickness, the strongest Raman spectrum peak, and the highest coverage of AIN particles.2, Using two-step growth method to grow the extension of AIN thin films, and adopting optimization growth data, the time of nucleation layer growth is 20 min. If growing the extension of AlN thin films under high temperature, the time is 60min, 120min and 180min separately. According to the analysis of SEM image, CL spectra, XRD and AFM three-dimensional images, it shows that the AlN thin films growth mode is stranski-Krastanov. The results of experiments demonstrate that the signal strength of AlN thin films is the strongest, the coverage is the highest and the surface is the smoothest.3, Using optimized AlN as buffer layer to grow SiC materials comparing with SiC which directly grows on the Si substrate, it shows that the unitary SiC will be got by growing SiC on the Si substrate with AlN as a buffer layer.