热管理用3英寸硅衬底金刚石薄膜的制备OA北大核心CSTPCD

The diamond film material holds great potential as a heat sink for GaN electronic devices.The diamond film layer with low stress,large dimensions,high quality,and an atomically smooth surface is crucial for enhancing the overall heat transfer capacity of GaN devices.This study presents a technique for growing and polishing polycrystalline diamond films on 3-inch(1 inch=2.54 cm)silicon substrates to facilitate the use of large-sized diamond film materials in radiator applications.Firstly,the study carries out multi-physical field self-consistent modelling of plasma in a microwave resonator.It then analyses the feasibility of depositing large diamond films using a microwave plasma chemical vapour deposition(MPCVD)device with a 2.45 GHz multi-mode ellipsoid resonator through simulation technology.The growth process parameters are optimized accordingly.After that,the diamond film is polished to meet the bonding requirements of GaN devices.The simulation results show that under the same microwave power input,the increase of chamber pressure leads to the increase of number density of plasma core electrons and H atoms,but the uniformity of radial distribution becomes worse.Diamond film is deposited under optimized conditions and mensurates that the thickness inhomogeneity of diamond film is 17%.In this process,methane at high concentration leads to pyramidal morphology of diamond grains dominated by(111)planes,accompanied by formation of twins.Full width at half maximum(FWHM)of the first-order characteristic peak of diamond in Raman spectrum is 7.4 cm-1.After polishing,the surface roughness reaches 0.27 nm,the average bending degree of diamond film on silicon substrate is 13.84 μm,and the average internal stress is-40.7 MPa.Silicon substrate diamond wafers with large size,high crystal quality,low internal stress and atomically smooth surface are successfully prepared by the above method.