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Bubble evolution in low energy and high dose He-implanted 6 H-SiC upon thermal annealing is studied. The(0001)-oriented 6 H-SiC wafers are implanted with 15 keV helium ions at a dose of 1×10~(17) cm~(-2) at room temperature. The samples with post-implantation are annealed at temperatures of 1073, 1173, 1273, and 1473 K for30 min. He bubbles in the wafers are examined via cross-sectional transmission electron microscopy(XTEM)analysis. The results present that nanoscale bubbles are almost homogeneously distributed in the damaged layer of the as-implanted sample, and no significant change is observed in the He-implanted sample after 1073 K annealing. Upon 1193 K annealing, almost full recrystallization of He-implantation-induced amorphization in 6 H-SiC is observed. In addition, the diameters of He bubbles increase obviously. With continually increasing temperatures to 1273 K and 1473 K, the diameters of He bubbles increase and the number density of lattice defects decreases.The growth of He bubbles after high temperature annealing abides by the Ostwald ripening mechanism. The mean diameter of He bubbles located at depths of 120-135 nm as a function of annealing temperature is fitted in terms of a thermal activated process which yields an activation energy of 1.914+0.236 eV.
The (0001) -oriented 6 H-SiC wafers are implanted with 15 keV helium ions at a dose of 1 × 10 ~ (17) The samples with post-implantation are annealed at temperatures of 1073, 1173, 1273, and 1473 K for 30 min. He bubbles in the wafers were confirmed via cross-sectional transmission electron microscopy (XTEM) analysis. The results present that nanoscale bubbles are almost homogeneously distributed in the damaged layer of the as-implanted sample, and no significant change was observed in the He-implanted sample after 1073 K annealing. Upon 1193 K annealing, almost full recrystallization of He In addition, the diameters of He bubbles increase obviously. With continually increasing temperatures to 1273 K and 1473 K, the diameters of He bubbles increase and the number density of lattice defects decreases. The growth o f He bubbles after high temperature annealing abides by the Ostwald ripening mechanism. The mean diameter of He bubbles located at depths of 120-135 nm as a function of annealing temperature is fitted in terms of a thermal activation process which yields an activation energy of 1.914 +0.236 eV.