Keithley 4200A-SCS

Appendix
L: Wafer-level reliability testing Model 4200A-SCS Parameter Analyzer
Reference Manual
L-10 4200A-901-01 Rev. C / February 2017
Figure 838: Process flow HCI/NBTI/constant current EM
V-ramp and J-ramp tests
Charge-to-breakdown measurement (Q
BD
) tests are a measure of time-dependent gate oxide
breakdown. They are a standard method used to determine quality of gate oxides in MOS devices.
The V-ramp test starts at the use-condition voltage (or lower) and ramps linearly from this value until
oxide breakdown. The J-ramp starts at a low current and ramps exponentially until oxide breakdown.
User modules for these tests are provided in the wlrlib user library. The user modules in the
wlrlib user library run linear regression and charge-to-breakdown (Q
BD
) ramp tests for wafer-level
reliability (WLR) testing. These user modules are summarized in the table below.
wlrlib user modules
User module Description
llsq1
Performs simple linear regression.
qbd_rmpv
Performs a charge-to-breakdown test using the
QBD V-ramp test.
qbd_rmpj
Performs a charge-to-breakdown test using the
QBD J-ramp test.