Improved and Expanded Reedholm Interface to UTMOST

In response to numerous recent changes in the GEM and PRN file formats output by Reedholm's EMAGE program, the Reedholm interface to Utmost 12.3.5 has been substantially rewritten. One advantage of this enhancement is that the need to supply a GEM file to Utmost has been eliminated. The PRN file format now solely supported is revision 1.06; later revisions cannot be guaranteed to be backwards compatible with the current interface.

Figure 1. PRN file selection screen.

 

The Reedholm interface is controlled via the Reedholm interface screen, accessed from the Utmost "Files" menu, which enables the pre-loading of a specified PRN file. All format checking is performed at this stage, and the message "Reedholm file loaded"indicates that the file has been successfully parsed. Subsequently setting the "Get Raw Data From" button on the System screen to"Reedholm File" makes the measured data available to those routines which are Reedholm-enabled.

There were twenty-one mosfet routines supported by the previous incarnation of the Reedholm interface; these routines are still supported by the new interface, and they are listed in table 1, below.Although no bipolar routines were previously supported, three of these have also now been Reedholm-enabled; these are listed in the table 2.(Note that the bipolar ALL_DC routine will only support the "All Forward" and "GP&BF" modes.)

 

UTMOST
Routine
Reedholm Sequence UTMOST
Routine
Reedholm Sequence UTMOST
Routine
Reedholm
Sequence
ID/VD-VG (1) S ID/VG-VB (2) F Leff,Rsd (3) F
Weef (4) F,F VTH (5) F Mobility (8) S,F
NSUB (9) F LAMBDA (11) S ETA (12) E
VMAX (13) E UCRIT (14) F LGAMMA (16) F
Doping (22) F ALL_SubV (23) S,F,F ALL_DC (24) S,F
VMAX Xnew (25) S ID/VG-VD (26) E IDRIVE (59) F
ISUBMAX (60) F BETA (79) F DL_new (81) F

Table 1: Summary of supported mosfet routines.

 

Utmost Reedholm Utmost Reedholm Utmost Reedholm
Routine Sequence Routine Sequence Routine Sequence
IC/CVE (1) B gummel (14) G ALL_DC (24) B,G

Table 2: Summary of supported bipolar routines.

 

The sequence of tests comprising a given PRN file must be consistent with the Utmost routine to be performed; however, the order in which multiple geometries are incorporated is arbitrary. The required tests are denoted in tables 1 and 2 by their Reedholm test types, "S", "F", "E", "B" and "G", as defined in Table 3. The precise configuration of each of these tests should be inferred from the documentation for the particular routine.

Table 3: Definition of Reedholm test types.

 

Utmost also imposes the following general requirements:

1) The EMAGE measurement mode must be set to "Fixed Scale".

2) The geometry of the device under test must be explicitly specified,in microns.

3) EMAGE uses the value "1.0000E20" to indicate a "dubious"measurement; these values will be interpreted literally by Utmost, so it is essential that their presence be eliminated, by re-measuring or interpolating as necessary, before attempting to supply data to Utmost.

4) The number of points measured on each curve in a multi-test routine must be invariant over the whole test sequence involved. For example,if 51 points are measured in each sweep of a given 'S' test, then 51points must also be measured in each seep of the corresponding 'F'test if the data is to be input into the mosfet ALL_DC routine.