Method of forming semiconductor devices having threshold switching devices

Forming a semiconductor device that includes a memory cell array may include performing a switching firing operation on one or more memory cells of the memory array to cause a threshold voltage distribution associated with threshold switching devices in the memory cells to be reduced. The switching device firing operation may be performed such that the threshold voltage distribution is reduced while maintaining the one or more threshold switching devices in the amorphous state. Performing the switching device firing operation on a threshold switching device may include heating the threshold switching device, applying a voltage to the threshold switching device, applying a current to the threshold switching device, some combination thereof, or the like.