Programmable nonvolatile memory and semiconductor integrated circuit device
View Patent ↗Distance λm between a floating gate and a drain contact of a floating gate transistor forming a memory cell is set to be greater than a distance λ determined based on a minimum design dimension between a control gate and a contact of a peripheral transistor. Data retention characteristics of a programmable memory which stores data in accordance with the amount of accumulated charges in the floating gate can be ensured without being affecting by mask misalignment or the like.
1. A programmable nonvolatile memory, comprising:
a memory cell including a memory cell transistor having first and second impurity regions formed at a surface of a substrate region and a charge accumulation region arranged on the substrate region between the first and second impurity regions for storing data in a nonvolatile manner according to an amount of charges accumulated in said charge accumulation region;
a first conductive line arranged corresponding to said memory cell transistor;
a first contact for electrically connecting the first impurity region with said first conductive line;
a peripheral transistor arranged in a region different from a region for arranging said memory cell on a common semiconductor substrate with said memory cell and used in other function than data storage, said peripheral transistor having third and fourth impurity regions formed at a surface of said semiconductor substrate and a control gate formed above the semiconductor substrate between the third and fourth impurity regions for receiving a signal for setting an on and off state thereof;
a second conductive line arranged corresponding to said peripheral transistor; and
a second contact for electrically connecting the third impurity region with said second conductive line, and
said charge accumulation region being a floating gate formed of a conductive material and a distance between said floating gate and said first contact being set to be greater than a distance between said second contact and said control gate.
2. The programmable nonvolatile memory according to claim 1 , wherein the distance between said floating gate and said first contact being set to be at least 1.2 times greater than the distance between said second contact and said control gate.