Semiconductor device comprising transistors having control gates and floating gate electrodes

Abstract

The semiconductor device comprises a first wellof a first conduction type formed in a semiconductor substrate; a second wellof a second conduction type formed in the first well; and a transistorincluding a control gateformed of an impurity region of the first conduction type formed in the second well, a first impurity diffused layerand a second impurity diffused layerformed with a channel regiontherebetween, and a floating gate electrodeformed on the channel regionand the control gatewith a gate insulation filmtherebetween. The control gateis buried in the semiconductor substrate, which makes it unnecessary to form the control gateon the floating gate electrode. Thus, the memory transistor and the other transistors, etc. can be formed by the same fabricating process. Thus, the fabrication processes can be less and the semiconductor device can be inexpensive.