Controlling the Capacitative Coupling

eprmex03.in : Controlling the Capacitative Coupling

Requires: SSuprem 4/DevEdit/S-Pisces
Minimum Versions: Athena 5.22.3.R, Atlas 5.28.1.R

This example consists of :

  • Dual gate EEPROM structure formation in Athena
  • Re-meshing in DevEdit
  • Threshold voltage simulation without a coupling capacitor
  • Definition of additional coupling capacitance
  • Threshold voltage simulation with a coupling capacitor
  • Plotting two threshold voltage curves for comparison

This example file is based upon that given in exprmex01.in but has an additional modification to account for capacitive coupling. A description of the standard syntax may be found in example eprmex01.in.

In a real device, the coupling between the control gate and the floating gate is a three-dimensional problem that depends upon the layout. As a result any two-dimensional simulation will not be able to accurately simulate coupling capacitance. In most cases it will underestimate this value. To take account of this problem Atlas is capable of connecting electrodes together via some capacitor. This effectively increases the coupling capacitance and can normally allow accurate matching to experimental data without having to make unphysical modifications to the structure.

This example consists of two Atlas input files. The first is a standard calculation of the threshold voltage from which the coupling ratio may be found. In the second, the syntax has been modified so that on the contact statement a capacitance is specified between the control and floating gates. After plotting the results it is apparent that the coupling ratio has been increased due to the additional coupling capacitance. This has effectively modified the threshold voltage.

To load and run this example, select the Load button in DeckBuild > Examples. This will copy the input file and any support files to your current working directory. Select the Run button in DeckBuild to execute the example.