| Summary: | 碩士 === 國立成功大學 === 材料科學及工程學系 === 89 === Abstract
Effects of C+ and N2+ implantation on the electrical properties of liquid-phase-deposition (LPD)Si(O,F) films as a function of the ion dose were studied. Upon C+ implantation some Si-F bonds were decomposed concurrently with the formation of Si-C and C-F bonds, resulting in an increase in the film density, from Fourier transform infrared spectroscopy (FTIR) and x-ray photoelectron spectroscopy (XPS) analysis. Carbon atoms tended to accumulate around the Si(O,F)/Si interface. The dielectric constant and leakage current were generally decreased with the C+ dose. The decrease of the dielectric constant of Si(O,F) films from 3.5 to 2.6 with increasing the C+ dose may be due to the formation of C-F and Si-C bonds. The replacement of oxygen in Si-O by C could reduce the ionic polarization and hence the dielectric constant. The reduction of leakage current by C+ implantation may be attributed to the passivation of the dangling bonds present at the Si(0,F)/Si interface and the increase of the film density due to the formation of Si-C bonds.
Upon N2+ implantation some Si-F bonds were decomposed concurrently with the formation of Si-N bonds such as Si2=N-O, ≣Si-N-Si≣, and Si3≣N, resulting in an increasing in the film density, from FTIR and XPS analysis. Nitrogen atoms tended to accumulate around the Si(O,F)/Si interface. The dielectric constant and leakage current were generally decreased with the N2+ dose. However, at 1 x 1015/cm2 the dielectric was increased. The decrease of the dielectric constant of Si(O,F) films from 3.8 to 2.8 with increasing the N2+ dose up to 7 x 1014/cm2 may be due to the formation of Si-N bonds. The replacement of oxygen in Si-O by N could reduce the ionic polarization and hence the dielectric constant. At 1 x 1015/cm2 the formation of substantial Si3≣N bonds made the Si(O,F) films more densified. The effect of films densification may exceed that of the decrease of the ionic polarization due to the formation of Si-N bonds and hence result in the increase of the dielectric constant of the Si(O,F) films. The reduction of leakage current by N2+ implantation may be attributed to the passivation of the dangling bonds present at the Si(0,F)/Si interface and the increase of the film density due to the formation of Si-N bonds.
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