A Schottky contact model was implemented as a boundary condition for a Monte Carlo device simulation. Unlike the ideal ohmic contact, thermal equilibrium is unnecessary around the Schottky contact. Therefore, the wide region of high impurity concentration around contacts is not required to maintain the thermal equilibrium, which means that it is possible to avoid assigning a lot of particles to the low-field region. The validity of the present boundary condition for contacts was verified by simulating a rectifying characteristic of a Schottky barrier diode. As an application example of the present boundary condition, we simulated the transport in n+nn+ structures with sub-0.1 μm channel length. We found direction dependence of the electron velocity dispersion, which indicates that the direction dependence of the diffusion constant or the carrier temperature should be taken into account in the hydrodynamic simulation for sub-0.1 μm devices.