TCAD Application Memory Devices Example 

Sentaurus Technology Template: SONOS Read/Write Operation 

This Sentaurus TCAD project provides a template for the simulation of the read/ write operation and the charge retention of a silicon-oxide-nitride-oxide-silicon (SONOS) nonvolatile memory device.

A SONOS memory device is based on a typical 0.13 µm NMOS structure with a nitride layer embedded in the gate stack. The program and erase states of the device are simulated for several cycles to achieve a stead-state charge density and then IdVgs curves are run to extract the corresponding threshold voltages. Lastly, a 10-year simulation is used to characterize the long-term charge retention capabilities of the SONOS structure.

Figure 1

Trapped electron and hole charge and total space charge in nitride region of SONOS device as a function of time during the program and erase cycles; corresponding applied gate bias is also shown

Figure 2

Concentration of electrons during the program cycle (left) and holes during the erase cycle (right) that tunnel into and out of the nitride region of the SONOS device

Figure 3

IdVg curve for program and erase states of SONOS device

Figure 4

Trapped electron and hole charge densities as a function of time are simulated for 10 years

The simulation project is part of the Sentaurus TCAD distribution at:


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