SiGe PMOS Process and Device Simulation

mos2ex12.in : SiGe PMOS Process and Device Simulation

Requires: SSuprem 4/Elite/Blaze
Minimum Versions: Athena 5.22.1.R, Atlas 5.22.1.R

This example demonstrates the interface from process to device simulation for a SiGe PMOS structure. Physical deposition and etch models are used to provide realistic topography. It shows:

  • PMOS process simulation using Athena
  • Specification of Ge mole fraction in Athena
  • Use of ELITE deposition and etching for contact topography
  • Definition of SiGe dopants
  • Interface to Atlas
  • Saving and plotting of the band structure for the SiGe/Si heterojunction.
  • Id/Vgs characteristic using Atlas

In this example a SiGe MOSFET structure is formed using process simulation. This contrasts with the previous examples in this section. To repeat the electrical analysis of the previous examples using this structure the Atlas simulation of this example should be replaced with the Atlas syntax for parameter settings, model selection, numerical methods and solve sequences from the previous examples.

The simulation of SiGe structures in Athena is similar to pure silicon MOSFET structures documented under the MOS examples section. The differences described here are limited to the special syntax needed for SiGe.

The Ge mole fraction in the deposited SiGe film is set by the c.frac parameter on the deposit statement.

In FLASH it is necessary to define whether a dopant is donor or acceptor explicitly for each material. The command impurity i.boron acceptor sige is used to set boron as a p-type dopant in SiGe. A similar command is used to define phosphorus as a donor.

The interface from Athena to Atlas is the simple go atlas statement. It saves the structure from Athena and transfers it to Atlas. No mesh statement is needed at the start of the Atlas run. The electrode statement in Athena is required to identify which regions are defined as electrodes in Atlas.

The Atlas run in this file is very simple. It solves only a single bias point with Vds=2.0V. To save the band structure the command output con.band val.band is used. This tells Atlas to save the conduction and valence band edge energies to any solution files saved using save . The final structure in Atlas is displayed using TonyPlot. The band diagram can be seen by taking a vertical 1D cross section in TonyPlot, selecting the 1D plot and changing the display variables from the scrolling list to be the two band edges.

For details on more complex applications of SiGe MOSFETs, users should consult the other MOS examples. All SPISCES analysis in these sections can be applied under Blaze to SiGe MOSFETs.

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