Roughness in silicon anisotropic etching: the influence of cleaning conditions

The surface contamination was known to affect the roughening during anisotropic etching. We studied the role of the initial surface states of silicon after different cleaning treatments (hydrogen-saturated, fluorine-saturated) over the way the etching proceeds. We investigated three types of ultimate-cleaning solutions after the standard RCA treatment: HF:H/sub 2/O 1:10 (followed by DI water rinsing and drying), HF:C/sub 2/H/sub 5/OH 1:10 (dried without any further rinsing), and 10% HCl in HF:H/sub 2/O 1:1 (also dried without rinsing). Since atomic scale roughness variations, as well as contamination affect the gate oxide integrity, we have correlated these results with electrical parameters extracted from C-V characteristics.