The effect of hydrogen ion implantation damage on the resistivity ofn-type 4H–silicon carbide is investigated. The variation of resistivity as a function of measurement temperature and postimplant annealing temperature is studied. Calculated resistivities obtained from resistance measurements are as high as8×106&OHgr; cm when resistances are measured at room temperature. When measured at 250 °C, the resistivity of the implanted layer is1×104&OHgr; cm. The resistivity is almost constant for annealings up to 1000 °C. The high-resistance behavior is believed to be related to implantation damage caused by 350 keVH+implantation. The results of this study can be used to obtain high-resistance regions for device isolation. ©1997 American Institute of Physics.