Negative electron beam resists composed of a phenylcarbinol, poly(4-hydroxystyrene) (PHS), and an onium salt have been developed to define patterns below 100-nm. Five phenylcarbinols were evaluated as a precursor of a dissolution inhibitor (PDI) and a water generator (WAG) which induces anisotropic acid-diffusion. 1,3,5-tris(2-(2hydroxypropyl))benzene (Triol(3)) was found to be the best PDI and WAG among the phenylcarbinols evaluated. Acid-diffusion measurement in a resist film containing Triol(3) clearly shows that the acid-diffusion coefficient in the exposed region is larger than that of the unexposed region. A resist consisting of PHS, Triol(3), and diphenyliodonium triflate (DIT) exhibits enough resolution (80-nm L&S), sensitivity (5-pC/cm2 at 50kV), and critical dimension control to define 100-nm L&S patterns. Spectroscopic studies indicate that the acid-catalyzed 0-alkylation of PHS hydroxyl groups by Triol(3) is responsible for the resist insolubilization.