TFIT2.0(TM)
Transistor Level Soft Error Analysis
Assess Your Soft Error Risk During Design
OVERVIEW
TFIT is a fast simulation tool which is used to predict and improve the SER and the FIT performance of cells design before production. TFIT allows reasonably accurate calculation of the electrical effect of particles impact to a transistor , a cell, or a circuit early in the design flow, at much faster speeds than traditional 3D TCAD simulations (whereas the 3D TCAD approach does not apply in the case of neutrons impact and circuits analysis) . Furthermore, TFIT can be customized to the users' technology just like internal TCAD effort, and integrate correlation with silicon test results. TFIT interfaces with Spice simulators so the electrical impact of the particle on a transistor is analyzed on a whole cell or circuit. Particles can be either neutrons (cosmic rays), alpha particles or heavy ions.
T-FIT IN THE DESIGN FLOW
T-FIT operates at the transistor electrical level and integrates into the standard design flows.
To use T-FIT, a designer needs to provide the following deign information:
- The technology of the target block: should exist in T-FIT database.
- The design description: SPICE netlist of the target block.
- The card model of the used transistors.
- Some geometrical data such as memory cell area and bulk depth (MCU case).
T-FIT KEY FEATURES
T-FIT has the following computation options:
- Simulate heavy ion impacts: in this mode the user can specify the list of particles (LET, Range) to simulate and the impacted transistors in the design. T-FIT will produce for each particle and transistor the effects of the impact on the circuit. These effects can be a flip of a memorizing cell or a pulse at the output of a logical gate. In addition T-FIT provides the induced impact currents and the simulation waves at the different nodes of the circuit.
- Compute a SEU FIT: In this mode the user specifies the transistors impacted in the design. Either the default neutron flux (JEDEC) or a user-defined flux can be used. T-FIT uses a nuclear database to retrieve information about the secondary particles that result from neutrons impacts with the silicon structure of the target design. TFIT characterizes the effects of the secondary particles on the circuit by using its technology response database and running SPICE simulations. TFIT returns the global FIT of the circuit and the contribution of each of the transistors specified.
- Compute MCU's FIT (New 2.0 release): Knowing the effects of neutrons impacts on one memorizing cell, TFIT computes the FIT values of the different MCU's that can occur in a memory array. TFIT do that by constructing a 3D representation of the memory array and by computing all possible multiple cells flips due to secondary particles passage through the structure. In addition to the FIT values TFIT provides the physical patterns of the MCU's.
