J. M. Mogollon

FTUNSHADES2: A novel platform for early evaluation of robustness against SEE

Large digital integrated circuits designed to solve space applications, have to be designed following standards that recommend to include hardening techniques against Single Event Phenomena caused by harsh radiation environments. It is specifically important in the case of modern deep-submicron technologies. Single Event Effects are phenomena related to the effects of radiation when ionizing particles hit the surface of semiconductors in certain critical areas, where the consequences are mainly data corruption or unexpected behavior with no permanent damage. Fault injection studies are a valuable methodology to evaluate the robustness of the circuit mainly in the early stages of the design. This paper introduces the second generation of the emulation-based fault injection platform FTUNSHADES supported by the European Space Agency, where new features have been included to fulfill with the demands of a growing community of users.

Mixed-Mode Simulation of Bit-Flip With Pulsed Laser

This paper shows an adaptation of the Sentaurus TCAD suite to pulsed laser SEE simulation. After the literature review, we present the model of the target transistor, calibrated against the HSPICE model of the foundry. The target model is used to evaluate the Linear Energy Transfer threshold for bit-flip in a simulated flip-flop circuit using the heavy-ion simulation tools of Sentaurus TCAD. Those simulations help us to make an adaptation of Sentaurus TCAD physical model for simulation of pulsed laser experiments. The pulsed laser simulation results are compared with a pulsed laser experiment, showing that the proposed model achieves more accuracy than previous models referred to in the literature.

Pulsed Laser SEU Cross Section Measurement Using Coincidence Detectors

This work presents the determination of a Pulsed Laser SEU Cross-Section (Count Statistics). In this work, a coincidence detector has been used to count fault events by comparing the digital VLSI circuit under test with a replica of the design running on a control FPGA. A SEU is declared when a specific fault pattern is detected. The target chip design generates specific fault patterns under pulsed laser shinning. Sweeping the laser energy on a flip flop of a Shift Register, data for a cross section analysis it is obtained. The coincidence detector was previously tested in a preliminary radiation test, so all the lessons learned in the design of radiation test can be translated for future works. In this work it has been used the pulsed laser facilities of Spanish National Laser Center in Salamanca.

TCAD Simulations on CMOS Propagation Induced Pulse Broadening Effect: Dependence Analysis on the Threshold Voltage

Propagation induced pulse broadening (PIPB) effect is becoming a major concern for electronic designers since new technologies are fast enough to propagate and capture Single Event Transients (SET). In this paper, we explore the influence of the MOSFET threshold voltage (VT) on PIPB effect by TCAD simulating the propagation of an SET after an ion strike, showing up this dependence by the modification of some CMOS technology parameters affecting VT. For this work, the test vehicle used to measure PIPB effect is a self-feedback chain of CMOS inverters. The conclusions outlined can be useful when designing with Multi-Vt nano-metric CMOS technologies. Our results suggest that the |VT|/VDD ratio could be a figure of merit for SET propagation broadening.

A Complete Emulation System for Single Event Effects Analysis

Trends show that next coming technologies will produce new generations of very large circuits, running at high clock rates. Some critical applications will have to be protected against the remaining radiation at sea level. This is especially important in aerospace applications because ionizing radiation produces corruption of the internal state. New design methods have to be introduced to assure circuits will tolerate the impact of single event effects (SEE). It is very important to be able to analyze which parts of the circuits are more critical and how the behavior of the global system is degraded when one part suffers a SEE. This paper presents the last functionalities added to the FT-UNSHADES system to extend the analysis to SETs and MBUs. As a result, the system can insert and analyze many fault types at a rate of 180 K faults per hour in a system with 2 million test vectors.

SEU Threshold model and its experimental verification

This work presents a simplified procedure to obtain the ionization profile from SRIM2010 and the Katz radial dose model applied to oxygen ions with kinetic energy from 12 to 18 MeV. Device simulation of Single Event Upsets needs LET(z) and w(z) (linear energy transfer and lateral radius) as inputs. TCAD simulations with the calculated ionization profile of a digital test chip predicts a SEU Threshold. That threshold is experimentally confirmed using the ion microprobe of the Tandem Van de Graaf accelerator at the CNA facility (Spain), validating the ionization model.

Real time SEU detection and diagnosis for safety or mission-critical ICs using HASH library-based fault dictionaries

Fault detection and diagnosis of safety and mission-critical embedded systems is a constant concern of the aerospace community. There exists a number of fault detection and diagnosis techniques, which are usually based on generating complicated models of the system, or increasing its redundancy. The present paper shows a new approach, based on hash libraries, which allows for fault detection and diagnosis at circuit level, without previous modeling of the system or adding redundancy. Additionally, the proposed technique can be used to detect faults in real-time in a final application, where no comparison with a golden chip is available.

TCAD mixed-mode simulation of bitflip with pulsed laser

Simulation of pulsed laser single event effects (SEE) is not considered in most of the well known software packages for mixed-mode simulation of SEE. This paper shows an adaptation of the Sentaurus TCAD suite to pulsed laser SEE simulation. After the literature review, we present the virtual model of the target transistor, calibrated against a real transistor of an specific ASIC. That virtual model is used to evaluate the Linear Energy Transfer (LET) threshold for bitflip in a simulated flip-flop circuit using the heavy-ion simulation tools of TCAD. That simulations help us to make an adaptation of Sentaurus TCAD for simulation of pulsed laser experiments. The pulsed laser simulation results are compared with a laser pulse experiment, showing that the proposed model achieves more accuracy than previous models referred to in the literature.

Metrics for the Measurement of the Quality of Stimuli in Radiation Testing Using Fast Hardware Emulation

Radiation Testing of unstructured digital circuits presents an extended set of difficulties related with detection and propagation of the faults to the primary outputs. Stimuli have to be chosen thinking on the possibility of propagating the faults through the logic to the primary outputs. Moreover, the set of stimuli should be selected to enhance the observability of both the time and location of the internal faults.

Simulation Methods for Ionizing Radiation Single Event Effects Evaluation

Single Event Effects (SEE) produced by highly energetic particle hits on sensitive circuit regions constitutes a main topic in reliability and device performance in space applications. Due to their high cost and limited availability, alternative methods to particle accelerator tests have been developed. In this sense, numerical simulations represent an excellent tool to predict device and circuit behaviour induced by particle hits. This paper deals with simulation techniques and their use in SEE study. Some different methods are shown and their possibilities to determine SEEs and their consequences on circuit behaviour are evaluated.