(100) Si and 4$^{circ}$off (100) Si were oxidized in dry oxygen, and the differences in thermal oxidation behavior and electrical characteristics between two specimens were investigated. Ellipsometer measurements of the oxide thickness produced by oxidation in dry oxygen from 1000 to 120$0^{circ}C$ showed that the oxidation rates of the 5$^{circ}$ off (100) Si were more rapid than those of the (100) Si and the differences between them decreased as the oxidation temperature increased. The activation energies based on the parabolic rate constant, B for (100) and 4$^{circ}$off (100) Si were 25.8, 28.6 kcal/mol and those on the linear rate constant, B/A were 56.8, 54.9 kcal/mol, respectively. Variation of C-V characteristics with the oxidation temperature showed that the flat band voltages were shifted positively and surface state charge densities decreased as the oxidation temperature increased, and the surface state charge density of the 4$^{circ}$off (100) Si was lower than that of the (100) Si. Also considerable decrease in the density of oxidation induced stacking faults (OSF) for the 4$^{circ}$off (100) Si was observed through optical microscopy after preferentially etching off the oxide layer.