Methods of forming semiconductor devices having threshold switching devices

A method, comprising:

• forming a memory cell array on a semiconductor substrate, the memory cell array including,
• a set of first conductive lines,
• a set of second conductive lines extending substantially perpendicularly to the first conductive lines, and
• a set of memory cells between the first conductive lines and the second conductive lines, the memory cells including data storage elements and threshold switching devices in an amorphous phase, each threshold switching device configured to change resistance based on a magnitude of a voltage applied on the threshold switching device at least meeting a threshold voltage associated with the threshold switching device, respectively;
• and
• performing a switching device firing operation on the memory cell array while maintaining the threshold switching devices in an amorphous state, such that a threshold voltage distribution associated with the threshold switching devices is reduced.