Sentaurus Device
7. Sentaurus Device at Runtime

7.1 Running Sentaurus Device
7.2 Log File
7.3 Version and Host Information
7.4 Active Math Parameters
7.5 Active Physical Models
7.6 Device Structure Files
7.7 Box Volume Statistics
7.8 List of Changed Parameters
7.9 Solve Report
7.10 Runtime Statistics

Objectives

7.1 Running Sentaurus Device

7.2 Log File

For each simulation, Sentaurus Device opens and exports to a log file all the runtime information relevant to the simulation. The file is named after the input command file with the extension .log. The information includes the Sentaurus Device version and the host machine, the device structure definition files, the active models and parameters applied, the solution report, and possibly error messages.

7.3 Version and Host Information

The Sentaurus Device version and host machine information is recorded at the beginning of the log file:

****************************************************************************
***                           Sentaurus Device                           ***
***                          Version N-2017.09                           ***
***                         (1.0, x86_64, Linux)                         ***
***                                                                      ***
***                       Copyright (C) 1994-2017                        ***
***                            Synopsys, Inc.                            ***
***                                                                      ***
***  This software and the associated documentation are confidential     ***
***  and proprietary to Synopsys, Inc.  Your use or disclosure of this   ***
***  software is subject to the terms and conditions of a written        ***
***  license agreement between you, or your company, and Synopsys, Inc.  ***
****************************************************************************

Running on machine with the following configuration:
Host Name: letay-vm-lnx
Operating System: Linux rel. 3.10.0-229.7.2.el7.x86_64 ver. #1 SMP Fri May 15\
 21:38:46 EDT 2015
Machine Type: x86_64
Process ID: 19250
Number of processors: 2
Domain Name: synopsys.com
Date: Thu Mar 16 18:17:41 2017  (CEST)

7.4 Active Math Parameters

The active math parameters can be found under "Numerical parameters" in the log file. The parameters define the error limits and error reference values used in the simulation:

Numerical parameters:
  Absolute error : 
    Poisson : 1.0000e-03
    eqPoisson : 1.0000e-03
    Electron : 1.0000e-05
    Hole : 1.0000e-05
    Photon-Rate-Equation : 1.0000e-07
    Photon-Phase-Equation : 1.0000e-05
    Rate-Stabilize-Equation : 1.0000e-07
    QW-Scattering-Equations : 1.0000e-05
    QW-eScattering-Equation : 1.0000e-05
    QW-hScattering-Equation : 1.0000e-05
    Optical Problem : 1.0000e-03
    Wavelength : 1.0000e-03
    Bandstructure : 1.0000e-03
...

7.5 Active Physical Models

Information about the physical models that were applied follows the "Physical models" record:

Physical models:
With SRH-Recombination
Without field dependent lifetimes
With doping dependent lifetimes
With temperature dependent lifetimes (power law)
Without thermal resistance interfaces
Without distributed resistance interfaces for electrons
Without distributed resistance interfaces for holes
Fermi Statistic
Intrinsic density models:
default bandgap model
Bandgap narrowing model: OldSlotboom with bandgap narrowing (Fermi)
Electron mobility:
Doping dependence:
Default
...

7.6 Device Structure Files

Information about the loaded device structure file is reported under the "Reading grid" record:

Reading grid 'n1_msh.tdr' ...
coordinate system: UCS, 3d_sprocess (x is device down direction)
use coordinate system as is (no transformation)
TDR format
Number of grid points is 3584.
done.

7.7 Box Volume Statistics

The box method volume statistics reported under the "non-Delaunay elements" record helps to analyze the mesh quality in terms of the number of poor-quality mesh elements and a BoxMethodVolume deviation from an actual physical device volume:

/-------- Region non-Delaunay elements\
 ------------------------------------------
Region                  Volume      BoxMethodVolume  DeltaVolume  Elements \
 non-Delaunay      non-DelaunayVolume
name                    [um2]          [um2]           [%]                  \
 Elements              [um2]   [%]
------------------------------------------------------------
R.Gateox             2.0400000e-04  2.0400000e-04     5.2e-13       696      \
 0 ( 0.00 %)   0.0000000e+00 ( 0.0000)
R.PolyReox           1.0000000e-03  1.0000000e-03     8.5e-14       157      \
 0 ( 0.00 %)   0.0000000e+00 ( 0.0000)
R.PolyReox_mirrored  1.0000000e-03  1.0000000e-03     1.2e-13       157      \
 0 ( 0.00 %)   0.0000000e+00 ( 0.0000)
R.Substrate          3.7000000e-01  3.7000000e-01     2.6e-12      4744      \
 0 ( 0.00 %)   0.0000000e+00 ( 0.0000)
R.Polygate           5.0000000e-03  5.0000000e-03     1.2e-12       742      \
 0 ( 0.00 %)   0.0000000e+00 ( 0.0000)
R.Spacer             4.4956237e-03  4.4956237e-03     4.5e-13       238      \
 0 ( 0.00 %)   0.0000000e+00 ( 0.0000)
R.Spacer_mirrored    4.4956237e-03  4.4956237e-03     5.6e-13       238      \
 0 ( 0.00 %)   0.0000000e+00 ( 0.0000)
............................................................
Total                3.8619525e-01  3.8619525e-01     4.0e-13      6972      \
 0 ( 0.00 %)   0.0000000e+00 ( 0.0000)
\------------------------------------------------------------
done.

7.8 List of Changed Parameters

New model parameters other than the defaults are reported under the "Reading parameters" record:

Reading parameter file 'pp2_des.par' ...
---------------------------------------------------
 Reading parameters for material "Silicon"
---------------------------------------------------

	Differences compared with default parameters:
	Scharfetter(elec): tau_max = 3.0000e-08, instead of: 1.0000e-05 [s]
	Energy relaxation time: tau_w_ele = 0.2, instead of: 0.3 [ps]
	Energy relaxation time: tau_w_hol = 0.2, instead of: 0.25 [ps]

...

7.9 Solve Report

This section discusses the different information available in the solve report.

7.9.1 Stepping Information

In Quasistationary sweeps, the t value is the virtual time, ranging between 0 and 1, that represents how much of the sweep goal has been reached. For example, t=0.352967 indicates that approximately 35% of the goal has been completed. In Transient sweeps, however, the t value refers to the real time measured in seconds:

Computing step from t=0.0000e+00 to t=0.1 (Stepsize: 0.1) :

The printed Stepsize is in terms of t.

7.9.2 Equations List

When solving the task for each time step, the following report is produced:

Computing step from t=0.0000e+00 to t=0.1 (Stepsize: 0.1) :
Computing Coupled( 5 circuit-equation(s) , 1 poisson-equation(s) , 
                   1 current-contact-equation(s) , 1 electron-equation(s) , 
                   1 hole-equation(s) ) 
using Bank/Rose nonlinear solver.

Iteration   |Rhs|      factor     |step|     error   #inner  #iterative  time
------------------------------------------------------------------------------
    0      3.73e+10                                                      0.07
    1      5.84e+09   1.00e+00   3.32e+00   1.13e+07    0         5      0.24
    2      4.19e+08   1.00e+00   9.58e-01   9.38e+04    0         5      0.42
    3      8.02e+07   1.00e+00   6.48e-01   9.91e+05    0         5      0.60
    4      5.90e+04   1.00e+00   3.52e-01   1.08e+04    0         5      0.78
    5      1.21e+00   1.00e+00   1.44e-05   7.70e-01    0         5      0.95
Finished, because...
Error smaller than 1 ( 7.6985E-01 ).

Accumulated times:
Rhs time:        0.47 s
Jacobian time:   0.08 s
Solve time:      0.39 s
Total time:      0.95 s

Device Instance nmos1:
Contact              Voltage              Electron      Hole         Conduction 
                 outer       inner        current       current      current
 drain        0.000E+00    0.000E+00      4.874E-16     2.304E-28    4.874E-16
 gate        -3.000E-01   -3.000E-01     -6.080E-36     6.080E-36    0.000E+00
 source       0.000E+00    0.000E+00      4.874E-16     5.322E-28    4.874E-16

where:

The Newton iterations are considered to have converged if the normalized error estimate becomes smaller than 1 or the normalized residual |Rhs| value becomes smaller than 10-5. This value can be changed using the keyword RhsMin in the Math section.

Newton iterations are considered to have failed to converge if any of these conditions are met:

If the Newton iterations failed to converge, the step size is reduced by default by a factor of 2. The step size is reduced further as needed, until the step size becomes smaller than the minimum step size (see Section 1.2.6 Solve Section). Then, the Quasistationary or Transient process terminates.

Sentaurus Device will start the next command in the Solve section, unless the flag ExitOnFailure is set in the Math section (see Section 1.2.5 Math Section). In this case, Sentaurus Device terminates the entire run.

If a Coupled statement outside of a Quasistationary or Transient statement fails, Sentaurus Device continues to the next command in the Solve section or terminates, as previously discussed.

If the Newton iterations converge within considerably fewer iterations than set by Iterations (see Section 1.2.5 Math Section), the step size increases by Increment until the MaxStep size is reached (see Section 1.2.6 Solve Section). In Transient, the Increment value exactly as specified is used; while for Quasistationary, the number of iterations, performed on a previous step, is considered for Increment computation.

7.10 Runtime Statistics

Information about runtime and memory use is located at the end of the log file:

******************************************************************************
Sentaurus Device process size: 563 megabytes
Sentaurus Device simulation times:
  wallclock: 95.34 s (0 h:01 m:35 s)
  total cpu: 89.58 s (0 h:01 m:29 s)
Sentaurus Device simulation finished (Date: Thu Mar 16 18:19:16 2017  (CEST)).
********************************* Good Bye ! *********************************

The reported memory use refers to the memory size at the end of the simulation. During the Sentaurus Device run, memory use might have been different due to the dynamic memory allocation by the simulator. To monitor actual memory consumption, it is recommended to use the UNIX top command during a task execution.

The wallclock time records the elapsed time between the launch of the Sentaurus Device job and its completion. The total cpu time records the time that the job was occupying a CPU. If other jobs are running on the computer at the same time, the wallclock time might be considerably larger than the total cpu time. It is recommended to specify the Wallclock keyword in the Math section to produce the correct timing report when running a simulation in parallel mode on multiple processors:

Math {
  ...
  Wallclock
}

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