NANOSIZE SILICON WHISKERS PRODUCED BY CHEMICAL-VAPOR-DEPOSITION - ACTIVE GETTERS FOR NF3

Nanosize whiskers on the order of 120 Angstrom in diameter have been p repared by chemical vapor deposition reactions of methyltrichlorosilan e and H-2 carrier gas on porous silica (Davisil) and other supports. T he porosity and composition of the support control the resultant size of the Si whiskers. NaY zeolite and C supports also allow formation of Si whiskers, however, silica gel leads to formation of spherical depo sits of Si on the order of 5 mu m. X-ray powder diffraction and line b roadening methods show that the whiskers are crystalline and are small particles. X-ray photoelectron spectroscopy shows the presence of ele mental Si in the CVD systems. Surface area measurements of the support s before and after CVD suggest that the pores of the support are still accessible after formation of Si whiskers. The Si whiskers on various supports have been used as outstanding getters for decomposition of N F3, a toxic gas which is used as an etchant for cleaning Si wafers in the semiconductor industry.