Test structure for determining boron diffusion coefficient in tungsten silicide

In order to study impurity diffusion in silicide, the authors patterned tungsten silicide into a line 2 mm long and 30 mu m wide and selectively implanted boron into a 40- mu m-long window. They modeled lateral diffusion profiles in this test structure and determined the diffusion coefficients of boron from SIMS (secondary ion mass spectrometry) line-scan profiles as 4.0*10/sup -10/ cm/sup 2//s at 650 degrees C, 9.5*10/sup -9/ cm/sup 2//s at 800 degrees C, and 2.0*10/sup -8/ cm/sup 2//s at 900 degrees C. This is more than 10/sup 6/ times larger than that in silicon. The results obtained make it possible to design a thermal process for half-micron dual-gate CMOS.<
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