Influence of a top Si3N4 layer on cavity formation and helium desorption in silicon

摘要

Specimens of silicon and silicon with a thermally grown Si3N4 layer were implanted at room temperature with 40 keV He ions at a dose of 5 x 10(16) ions/cm(2). TransmSUsion electron microscopy (TEM) and thermal desorption spectroscopy (THDS) have been used to investigate the effects of the Si3N4 layer on cavity growth and thermal release of He atoms. TEM reSUlts show that the presence of the top Si3N4 layer can SUppress the growth of cavities after SUbsequent annealing at 800 degrees C for 1 h. The thermal desorption reSUlts reveal that the top Si3N4 layer can act as an effective barrier to the permeation of He from bubbles to the SUrface, which gives rSUe to dSUappearance of the weak release peak at the low temperature region and occurrence of a new release peak at the intermediate temperature region. The reSUlts are qualitatively dSUcussed. (