Patent ID: 9147690
Filing Date: 2015-09-29
Classification: G11C,H01L

Abstract:
1. An erasable programmable single-poly nonvolatile memory, comprising: a substrate structure; a first PMOS transistor comprising a select gate, a first source/drain region, and a second source/drain region, wherein the select gate is connected to a select gate voltage, and the first source/drain region is connected to a source line voltage; a second PMOS transistor comprising the second source/drain region, a third source/drain region, and a floating gate, wherein the third source/drain region is connected to a bit line voltage and the first source/drain region, the second source/drain region, and the third source/drain region are constructed in a N-well region; an erase gate region adjacent to the floating gate, wherein the erase gate region comprises a first n-type region connected to an erase line voltage and a P-well region, wherein the N-well region and the P-well region are formed in the substrate structure; and a first isolation structure and a second isolation structure formed in the substrate structure, wherein the first isolation structure is located between the N-well region and the P-well region, and the erase gate region is located between the first isolation structure and the second isolation structure; wherein a plurality of electrons are transmitted through a channel region of the second PMOS transistor to the floating gate and the electrons are injected into the floating gate in a programmed state; and the electrons are removed from the floating gate and discharged out of the erasable programmable single-poly nonvolatile memory through the first n-type region in an erased state; wherein the P-well region comprises: a first p-type region formed under a surface of the substrate structure and contacted to the first n-type region; a plurality of second p-type regions formed under the first isolation structure and the second isolation structure; and a third p-type region formed under the first p-type region; wherein the first p-type region and the third p-type region are located between the second p-type regions, and both the first p-type region and the third p-type region are directly contacted to the second p-type regions; and wherein a dosage in the second p-type regions is higher than a dosage in the first p-type region, and a dosage in the third p-type region is higher than or equal to the dosage in the first p-type region.