Abstract:
A single-poly EEPROM cell is disclosed with a vertically formed metal-insulator-metal (MIM) coupling capacitor, which serves as a control gate in place of a laterally buried control gate thereby eliminating the problem of junction breakdown, and at the same time reducing the size of the cell substantially. A method of forming the single-poly cell is also disclosed. This is accomplished by forming a floating gate over a substrate with an intervening tunnel oxide and then the MIM capacitor over the floating gate with another intervening dielectric layer between the top metal and the lower metal of the capacitor where the latter metal is connected to the polysilicon floating gate.
Abstract:
A split-gate flash memory cell having improved programming and erasing speed with a tilted trench source, and also a method of forming the same are provided. This is accomplished by forming two floating gates and their respective control gates sharing a common source region. A trench is formed in the source region and the walls are sloped to have a tilt. A source implant is performed at a tilt angle and the trench is lined with a gate oxide layer. Subsequently, a lateral diffusion of the source implant is performed followed by thermal cycling. The lateral enlargement of the diffused source is found to increase the coupling ratio of the split-gate flash memory cell substantially.
Abstract:
A split-gate flash memory cell having improved programming and erasing speed with a tilted trench source, and also a method of forming the same are provided. This is accomplished by forming two floating gates and their respective control gates sharing a common source region. A trench is formed in the source region and the walls are sloped to have a tilt. A source implant is performed at a tilt angle and the trench is lined with a gate oxide layer. Subsequently, a lateral diffusion of the source implant is performed followed by thermal cycling. The lateral enlargement of the diffused source is found to increase the coupling ratio of the split-gate flash memory cell substantially.