Oxidation experiments were performed on structures which consisted of polycrystalline Si on thin oxides. The results indicated that some of the interstitials which were generated were partially trapped within the polycrystalline layer, while others escaped. These diffused through the underlying oxide and affected pre-grown oxidation-induced stacking faults in the Si. The trapping efficiency of the polycrystalline film was found to increase with decreasing grain size or increasing film thickness. This indicated that grain boundary traps were mainly responsible for interstitial trapping within the polycrystalline silicon. The greater trapping efficiency of films with a smaller grain size was attributed to the larger area of grain boundary and the higher grain boundary trap concentration in that case. In all cases, polycrystalline Si films trapped more interstitials than did crystalline Si films of the same thickness.

D.Tsoukalas, D.Kouvatsos: Applied Physics Letters, 1996, 68[11], 1549-51