Fluid ejection devices comprising memory cells

A fluid ejection device comprising:

• a substrate;
• and
• an array of memory cells on the substrate, wherein a first memory cell of the array of memory cells comprises:
• a control gate;
• a first dielectric layer under the control gate;
• a floating gate capacitively coupled to the control gate through the first dielectric layer, the floating gate comprising a polysilicon layer, a metal layer, and a second dielectric layer between the polysilicon layer and the metal layer, wherein the second dielectric layer includes an opening through which the polysilicon layer is electrically connected to the metal layer;
• a third dielectric layer under the floating gate;
• and
• a channel region capacitively coupled to the floating gate through the third dielectric layer and between a drain region and a source region, wherein the drain region overlaps the third dielectric layer a first distance, and the source region overlaps the third dielectric layer a second distance such that an effective length of the channel region between the drain region and the source region is greater than or equal to a sum of the first distance and the second distance.

A printhead comprising:

• a substrate;
• and
• a memory cell on the substrate and comprising:
• a channel region formed in the substrate between a drain region and a source region;
• a first dielectric layer over the channel region;
• a floating gate capacitively coupled to the channel region through the first dielectric layer, the floating gate comprising a polysilicon layer, a metal layer, and a second dielectric layer between the polysilicon layer and the metal layer, wherein the second dielectric layer includes an opening through which the polysilicon layer is electrically connected to the metal layer;
• a third dielectric layer over the floating gate;
• and
• a control gate capacitively coupled to the floating gate through the third dielectric layer.