1. A method of programming a nonvolatile memory cell comprising a steering element located in series with a storage element, wherein the storage element comprises a carbon material, the method comprising: applying a reset pulse to change a resistivity state of the carbon material from a first state to a second state which is higher than the first state; and applying a set pulse to change a resistivity state of the carbon material from the second state to a third state which is lower than the second state, wherein a fall time of the reset pulse is shorter than a fall time of the set pulse.