Nanosize whiskers on the order of 120 Å in diameter have been prepared by chemical vapor deposition reactions of methyltrichlorosilane and H2 carrier gas on porous silica (Davisil) and other supports. The 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 deposits of Si on the order of 5 gm. X-ray powder diffraction and line broadening methods show that the whiskers are crystalline and are small particles. X-ray photoelectron spectroscopy shows the presence of elemental Si in the CVD systems. Surface area measurements of the supports 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 NF3, a toxic gas which is used as an etchant for cleaning Si wafers in the semiconductor industry.
All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)
- Materials Chemistry