The time- and temperature-dependences of permeation through this oxide, and into polycrystalline Si, were studied. It was found that the presence of the oxide layer caused the D flux into the underlying Si to decrease by more than 4 orders of magnitude, as compared with Si without an oxide layer. When the oxide was thicker than 0.1, the D flux was independent of the hydrogenation time. However, the direct exposure of polycrystalline Si to monatomic D exhibited a power-law decrease in the D flux with time. In the absence of an oxide layer, the D flux exhibited a weak temperature dependence; with an activation energy of 0.31eV. The activation energy did not change significantly for diffusion through an oxide (figure 7); thus indicating that an increase in barrier height could not account for the striking decrease in D flux.

N.H.Nickel, W.B.Jackson, I.W.Wu, C.C.Tsai, A.Chiang: Physical Review B, 1995, 52[11], 7791-4