A detailed study was made of attempts to suppress the penetration of B into p-type metal oxide semiconductor field-effect transistors. Four types of polycrystalline Si gate structure and 2 types of gate dielectric were considered for the suppression of B penetration. A stacked amorphous Si structure was found to be the most effective means of retarding B penetration. The use of N2O led to a superior retardation of B diffusion. It was found that the use of a combination of stacked amorphous Si, and N2O, was the most effective method for preventing B penetration.

T.S.Chao, C.H.Chu, C.F.Wang, K.J.Ho, T.F.Lei, C.L.Lee: Japanese Journal of Applied Physics, 1996, 35[1-12A], 6003-7