New Features in UTMOST Version 12.03.0


The major new features which will be available in this year's UTMOST release will be detailed in this article. Important bug fixes which were implemented since the last official release of UTMOST will also be described. The last official release of UTMOST was UTMOST Version 10.10.1 and the upcoming release will be Version 12.03.0 UTMOST will be available the following platforms:


Work Station Type Operating System
Sun SPARC and superSPARCSolaris 1 -> SunOS 4.1.3 and 4.1.4
Solaris 2 -> Solaris 2.4 and up
HP9000/700 series HP C, J and K series HPUX 9.05 and up
IBM RS6000 series AIX 3.2.5 and up
DEC Alpha AXP series DIGITAL UNIX (OSP) Version 3.2 and up
SGI workstationsIRIX 5.3 and up

Bug Fixes

The following major bugs were fixed since the release of UTMOST Version 10.10.1:

  • In version 10.10.1 the path to the VYPER installation directory had to be less than 23 characters long for stable UTMOST operation. This restriction is eliminated.
  • Problems associated with the definition, in VYPER, of empty path names to external SPICE simulators is eliminated.
  • The Data Setup option for the FT plots routine which was disabled in UTMOST 10.10.1 is re-introduced.
  • Instabilities due to UTMOST warnings, displayed as a result of saving a model to a model library, are removed.
  • Random time-out errors associated with S-parameter measurements is fixed.
  • The biasing of BJT devices during ALL_DC reverse gummel measurements in common-base mode is corrected.

New Features

The following are the major new features which are developed and implemented into UTMOST since the release of UTMOST Version 10.10.1.


Plots of device transconductance divided by current (gm/IDS) can now be plotted using the MOS ALL_DC routine (see Figure 1). The UTMOST Replots environment has a new Overlay feature (see Figure 2). This feature will work with single plot routines such as ID/VG-VB for MOS and gummel for BIP technologies.

Figure 1. Plot showing measured and simulated gm/IDS curves.

Figure 2

Figure 2. UTMOST replot screen showing three sets of overlayed curves.

Local Optimization

There are a number of new capabilities associated with the UTMOST local optimization facility. These include a local optimization strategy copy option, local optimization strategy delete option and separate minimum and maximum optimization target limit columns the local optimization Current+Deriv mode. If a parameter reaches its specified optimization boundary limits as a result of a local optimization step then this parameter will now be highlighted in the Local Optimization window as well as in the Parameters window. Optimization target limits for device current (per sweep basis) can now be specified in terms of percentages of maximum measured current on a logarithmic scale as well as on an absolute scale. The maximum number of steps in any local optimization strategy, as well as the maximum number of parameters in any local optimization step, have been increased. The fit and local optimization functionalities have been separated so that they can be used independently of each other.

New Models

The MEXTRAM BJT model, the BSIM3 Version 3 (BSIM3v3) MOSFET model, the Philips Level 9 MOSFET model (MM9), the EKV MOSFET model, the MASTAR MOSFET model, and amorphous and polysilicon TFT models have been added to the list of supported models in UTMOST. Models which have been implemented using the SmartSpice C Interpreter can now be accessed by UTMOST. The SmartSpice Interpreter is an excellent tool for the analysis and debugging of new device models. Models which exist in any SPICE Model file can now be listed using a new SPICE Model File Summary option in UTMOST.

New Technologies

TFT (Thin Film Transistor), SOI (Silicon On Insulator), and HBT (Hetro-junction Bipolar Transistor) technologies are added to the list of supported technologies in UTMOST.

New MOSFET Test Routines

The BSIM3 routine is enhanced so that BSIM3v2 or BSIM3v3 parameters can be extracted. Many of the restrictions associated with the previous BSIM3 routine, with respect to device geometry selection, have also been relaxed. Additionally, the BSIM3 routine will cater for devices measured on more than one test structure group (module).

A new MOSFET substrate current routine, called ALL_ISUB, enables the measurement of multi-geometry ISUB vs VGS curves and the subsequent optimization (global or local) of associated model parameters (see Figure 3).

Figure 3

Figure 3. Plot showing measured and simulated substrate current versus VGS plots for NMOS devices.

New measurement and analysis routines have been added for the measurement and extraction of MASTAR MOSFET model parameters, EKV MOSFET model parameters and channel length and width reduction parameters (BETA and DL_NEW routines).

Substrate current measurement and analysis is now also available for BJT devices using the gummel routine.

S-Parameter Measurements

The implementation of UTMOST S-parameter measurements is improved so as to eliminate random time-out errors which some UTMOST users were experiencing. The maximum number of bias points available for S-parameter measurement and analysis in UTMOST is increased. In addition, 3-step de-embedding is now supported in UTMOST.

Batch Mode

The UTMOST batch mode command list is updated to include commands which will select a current working directory, select a specific wafer die (or all wafer die) from an UTMOST Log file containing data measured from more than one die, assign a value from a Fitting parameter to a Model parameter, and create data for the ALL_DC routine from ID/VG-VB and ID/VD-VG data.

Measurement Issues

A driver for the Electroglas 4080 prober is added. Enhancements to the HP4155/56 driver are implemented allowing for the control of the ground unit and for the use of the instrument in user mode. The definition of various GPIB/RS-232 parameter settings such as serial port names, baud rates, etc., are made more flexible (see Figure 4) . Utmost will also support internal GPIB cards in HP9000/700 series computers.

Figure 4

Figure 4. Serial Port Setup window configured for a SUN workstation.

Measurement Log Files

Data stored in an UTMOST Log file which was measured from different groups (modules) can now be merged in UTMOST so that the data looks as if it was measured from a single test group or module. This will allow multi-geometry optimizations (e.g. MOSFET ALL_DC routine) to be performed on device measurements taken from different modules.

A rapid file close option is added for UTMOST Log files. This will enable very large Log files to be closed quickly but at the expense of the exclusion of the various sanity checks which are normally performed on these files prior to them being closed.