We live on a radioactive planet bombarded with cosmic rays and high-energy neutrons. These cause two big problems. First, single-event-effects (SEE) including single-event-burnout (SEB) and single-event-gate-rupture (SEGR) whereby a high-energy particle can cause a bit to flip in a memory or a flop to change its value or device destruction. This can obviously cause the entire system to malfunction temporarily or fail irreparably.

A second effect is that the build up of the dose of radioactive particles can cause threshold shifts in the transistors which can result in long-term reliability issues. Since there is less protection from the earth’s magnetic field, this is especially a problem with space-borne systems and even avionics but any devices with very long planned lifetimes, such as the 20-year lifetime for automobiles, needs to be concerned about this. In sub 28nm process technology nodes used for commercial applications like high end servers, design teams are increasingly paying attention to SEE even in a terrestrial environment as very little energy is required to flip a bit.

Silvaco can model these effects from what is, in effect, first principles. In addition, recently declassified technology for measuring threshold shifts allows the long-term effects to be analyzed accurately. Besides soft error reliability and total dose analysis, Silvaco’s TCAD simulation also supports aging effects such as NBTI and HCI.

TCAD forms the foundation of radiation analysis, building up a model of the device from the process recipes. Some modeling can be done at the TCAD level but analysis of more than a single device is best done by using the TCAD modeling to create SPICE models and then analyzing at the circuit level. Silvaco’s model extraction capability creates a bridge between the TCAD and SPICE simulation worlds. Post-radiation (or aged) compact models can be created, such as modeling the circuit for how it might be expected to behave after a decade. In addition, mixed TCAD and SPICE mode simulations can be run so that a radiation strike analyzed in TCAD on a single device can be propagated through for analysis as part of a SPICE circuit simulation.

3D SEU Simulation with mesh refinement along strike path

 

In advanced technology nodes where power density increases, EM analysis is a key reliability verification step in a design flow. More resistive metal layers close to silicon make IR drop analysis critical to ensure functionality. Active device heating and its impact on EM and IR need to be considered concurrently. Silvaco provides EM/IR/Thermal analysis capabilities as part of its reliability suite of products.

InVar Thermal Analysis

Silvaco’s SmartSpice circuit simulator supports TSMC’s TMI2 interface enabling it to support aging and self-heating models that are part of FinFET technology nodes.

Capabilities

TCAD
  • Single Event Burnout (SEB)
  • Single Event Gate Rupture (SEGR)
  • Single Event Effects (SEE)
  • Total Dose Including Hole De-trapping Model
  • Dose Rate
  • Mesh Refinement Along Strike Track
  • NBTI and HCI
  • Mixed-mode TCAD/SPICE Simulation
Model Extraction
  • TCAD to SPICE Link to Build Aged Models and Post-strike Models
SPICE Simulation
  • SEE and Total Dose Analysis
  • Quenching Model
  • TMI2 Support for Aging and Self-Heating
Variation-Aware Design
  • Fast Monte Carlo analysis to save simulation runs; Local mismatch analysis
  • Statistical corners for quick design iterations
  • High sigma design for medical, automotive applications
Custom Design
  • Full Custom Layout
  • Integrated Extraction and DRC/LVS
Extracted Netlist Analysis & Reduction
  • Parasitic Reduction
  • Design Analysis
  • Comparison of extracted netlist with parasitics
Invar
  • Block to Full-chip Level Analysis
  • Early layout IR/EM analysis
  • SPICE Accuracy