Stephen Buchner

Subbandgap laser-induced single event effects: carrier generation via two-photon absorption

Carrier generation based on subbandgap two-photon absorption is demonstrated and shown to be a viable alternative to the conventional single-photon excitation approach in laser-induced single event effects. The two-photon approach exhibits characteristics distinct from those of single-photon excitation, and may be advantageous for a range of single-event effect investigations. The charge track produced by two-photon absorption more closely resembles that of heavy-ion irradiation and, because the photon energy is subbandgap, backside injection through bulk silicon wafers is straightforward and three-dimensional mapping is possible.

Application of a pulsed laser for evaluation and optimization of SEU-hard designs [CMOS]

Pulsed laser single-event upset tests are used to pinpoint and characterize sensitive nodes of circuits and to provide feedback relevant to the development and optimization of radiation-hard designs. The results presented reveal the advantages of incorporating laser evaluation at an early stage into programs described for the development of radiation-hardened parts. A quantitative correlation is observed between the laser single-event upset and single-event latchup threshold measurements and those performed using accelerator-based heavy ion testing methods.

Three-dimensional mapping of single-event effects using two photon absorption

Carrier generation based on subbandgap two-photon absorption is used to perform three-dimensional mapping of the single-event transient response of the LM124 operational amplifier. Three classes of single-event-induced transients are observed for the input transistor Q20. A combination of experiment and transistor level modeling is used to assign the different classes of measured transients to charge collection across specific junctions. The large-amplitude, positive-going transients cannot be assigned to a single junction, and are identified with a collector-substrate photocurrent.

Comparison of SETs in bipolar linear circuits generated with an ion microbeam, laser light, and circuit simulation

Generally good agreement is obtained between the single-event output voltage transient waveforms obtained by exposing individual circuit elements of a bipolar comparator and operational amplifier to an ion microbeam, a pulsed laser beam, and circuit simulations using SPICE. The agreement is achieved by adjusting the amounts of charge deposited by the laser or injected in the SPICE simulations. The implications for radiation hardness assurance are discussed.

Pulsed laser-induced single event upset and charge collection measurements as a function of optical penetration depth

We use picosecond laser pulses to investigate single event upsets and related fundamental charge collection mechanisms in semiconductor microelectronic devices and circuits. By varying the laser wavelength the incident laser pulses deposit charge tracks of variable length, which form an approximation to the charge tracks resulting from high energy space particle strikes. We show how variation of the charge track length deposited by laser pulses allows the mechanisms of charge collection in semiconductor devices to be probed in a sensitive manner. With the aid of computer simulations, new insight into charge collection mechanisms for metal–semiconductor field effect transistor (MESFET) devices and heterojunction bipolar transistor devices is found. In the case of the MESFET we point out the correlation between charge collection in the device and the ensuing single event upset in the composite circuit. In favorable cases, we show how probing circuits with tunable laser pulses can estimate a charge collectio...

Demonstration of single-event effects induced by through-wafer two-photon absorption

The first demonstration of through-wafer two-photon absorption (TPA) single-event effects (SEEs) testing is presented. We interrogate the single-event transient (SET) response of several different nodes of the LM124 operational amplifier via TPA carrier injection through both the front and back (substrate) chip surfaces. The results reveal that the SETs and sensitivities produced in several different nodes by front-side and back-side irradiation are effectively identical, confirming the validity of this approach for SEE studies.

Single-event effects ground testing and on-orbit rate prediction methods: the past, present, and future

Over the past 27 years, or so, increased concern over single-event effects (SEEs) in spacecraft systems has resulted in research, development, and engineering activities centered around a better understanding of the space radiation environment, SEE predictive methods, ground test protocols, and test facility developments. This research has led to fairly well developed methods for assessing the impact of the space radiation environment on systems that contain SEE sensitive devices and the development of mitigation strategies either at the system or device level. However, as new technology has emerged, these ground test and predictive methods have certain short falls.

Fault Simulation and Emulation Tools to Augment Radiation-Hardness Assurance Testing

As of 2013, the gold standard for assessing radiation-hardness assurance (RHA) for a system, subsystem, or a component is accelerated radiation testing and/or pulsed laser testing. Fault injection tools, which include both fault simulation and emulation tools, have become more common in the last 15 years. Fault simulation tools use analytical methods for assessing RHA, whereas fault emulation uses hardware methods. Both fault simulation and emulation allow designers to augment traditional RHA techniques to determine whether circuit designs, microarchitectures, components, and application-specific integrated circuits (ASICs) meet the requirements for a particular mission. Fault simulation and emulation can provide the designers the luxury of testing on the benchtop without the time and financial constraints of accelerated radiation testing. This paper explores how to design, implement, and validate a fault simulation or emulation system. The paper ends with several case studies of currently used fault simulation and emulation systems.

Critical charge for single-event transients (SETs) in bipolar linear circuits

The critical charge for single-event transients (SETS) from heavy ions has been simulated and measured in bipolar linear circuits under several bias conditions. Although in many cases the threshold linear energy transfer is less than 2 MeV-cm/sup 2//mg, the minimum critical charge is of the order of 0.3-1 pC.

Current single event effects and radiation damage results for candidate spacecraft electronics

We present data on the vulnerability of a variety of candidate spacecraft electronics to proton and heavy ion induced single event effects, proton-induced damage, and total ionizing dose. Devices tested include optoelectronics, digital, analog, linear bipolar, hybrid devices, analog-to-digital converters (ADCs), digital-to-analog converters (DACs), and DC-DC converters, among others.