New amorphous-silicon electrically programmable nonvolatile switching device

Preliminary data on the characteristics of an electrically programmable nonvolatile semiconductor memory device fabricated from amorphous silicon are reported. The device consists of a p- and an n-layer deposited onto conducting stainless-steel substrates, with a third undoped quasi-intrinsic layer added to stabilize performance. For most configurations, the first switching operation is unique, occurring at a considerably higher threshold voltage than subsequent cycles and being necessary for operation as a nonvolatile device. The device is switched between the ON (WRITE) and OFF (ERASE) states by voltages of opposite signs, with thresholds for the WRITE and ERASE operations of 4-8 and about 1 V, respectively. Experimental devices have been switched through 100,000 cycles, and have been found stable in ON and OFF states for several weeks. The device exhibits extremely fast transition times and requires very low energy (less than 10 to the -6th J) for the switching transition.