A nonvolatile memory cell and non-volatile memory cells and university as well as processes for their preparation

摘要

A nonvolatile memory has: (a) second conductivity type common source, programming/read drain and monitor drain connections (32, 33, 34) spaced apart below a first conductivity type semiconductor substrate (42) surface; (b) a tunnelling insulation layer (40) on the substrate (42) between the common source and programming/read drain connections (32, 33); (c) an insulating layer (41) on the substrate (42) between the common source and monitor drain connections (32, 34); (d) a floating gate (31) on the tunnelling insulation and insulating layers (40, 41); and (e) a control gate (30) on a dielectric layer (44) above the floating gate (31). Also claimed is a process for producing the above nonvolatile memory. The nonvolatile memory has: (a') spaced-apart alternate first and second impurity regions (32, 33) below the surface of a first conductivity type semiconductor substrate (42); (b') several insular tunnelling insulation layers (40) on the substrate (42), each located between a second and a first impurity region at one side of the middle of the first impurity region; (c') an insulating layer (41) on the substrate (42) but not on the tunnelling insulation layers (40); (d') several floating gates (31), each lying on one of the tunnelling insulation layers (40) and on the insulating layer (41) portion located on the other side of the middle of the first impurity region between another second impurity region and the first impurity region; and (e') several word lines (30) on the floating gates (31) at right angles to the first and second impurity regions (32, 33).