Investigation of the Parameters of Layers Prepared through Diffusion of Boron and Gadolinium from Silicate and Hybrid Films into Silicon Wafers

摘要

This paper reports on the results of investigations into the main electrical parameters of diffusion layers formed in silicon due to the annealing of films containing boron and gadolinium. The sources for boron and gadolinium diffusion are silicate and hybrid organic-inorganic films prepared by the sol-gel method. It is demonstrated that small amounts (0.5-2.0 wt %) of organic additives, i.e., polyols with different structures and different molecular weights, favor the formation of layers with the highest possible concentration of the boron dopant at a level of the boron solubility limit in silicon (N_s = 5-7 x 10~(20) cm~(-3)) with a diffusion layer depth ≥4μm. The electrical parameters determined for the diffusion layers with the use of the Irwin concentration curves and the data obtained by secondary ion mass spectrometry are compared. The diffusion coefficients of boron and gadolinium are calculated. These data for gadolinium are obtained for the first time. It is revealed that the process of boron diffusion is retarded when boron is introduced in combination with gadolinium.