Nonvolatile semiconductor memory device with high impurity concentration under field oxide layer

摘要

Flash type programmable nonvolatile memory unit cells are provided, along with a manufacturing method. Each unit cell is formed such that the interpoly dielectric layer and the control gate surround the top surface and also the four lateral surfaces of the floating gate. This increases the capacitance between the floating gate and the control gate, which improves a coupling ratio. This also improves electromagnetic shielding within each cell, which reduces cross talk between neighboring cells, and permits more dense integration.