LM124 Operational Amplifier Research Articles

New Approach for Pulsed-Laser Testing That Mimics Heavy-Ion Charge Deposition Profiles

A novel approach for two-photon absorption (TPA) pulsed-laser testing produces extended charge deposition profiles that are analogous to those produced by heavy ions. In this approach, which utilizes an axicon rather than a spherical lens, the conventional Gaussian beam is replaced by a quasi-Bessel beam. The key feature of a quasi-Bessel beam, relevant to pulsed-laser single-event effects (PL-SEE) studies, is that its radial size ( $\sim 1~\mu \text{m}$ ) remains constant over the axial length of the beam (several 100 s of $\mu \text{m}$ ) resulting in a charge-deposition profile that more closely mimics that produced by a heavy ion. This elongated charge distribution directly lends itself to a simple and intuitive description in terms of linear-energy transfer (LET), facilitating laser/ion correlation studies. Experimental results comparing a conventional TPA PL-SEE focusing geometry and the axicon focusing geometry are presented for three different test vehicles: a 45-nm silicon-on-insulator (SOI) nFET, a bulk silicon photodiode, and an LM124 operational amplifier. By using the axicon approach, strong laser/ion correlation is observed in the silicon photodiode for single-event transients (SET) across a wide range of LETs. The correlation is achieved by “tuning” the laser to the desired LET rather than relying on preexisting heavy-ion data, and therefore, this approach holds promise as a predictive tool.

Atypical Effect of Displacement Damage on LM124 Bipolar Integrated Circuits

LM124 operational amplifiers from three different manufacturers are irradiated with 60Co gamma rays and neutrons. During neutrons irradiation, one of the three integrated circuits exhibits an unexpected slew rates increase while its open loop gain and supply bias current follow the usual monotonic decrease as described in the literature. Analysis at circuit level shows that this phenomenon is due to an increase in the radiation-induced base current of the transistor used as buffer stage in the amplification chain. It is then demonstrated that a slight modification of the buffer transistor design, which is not implemented on the two other devices, enhances this phenomenon. Finally, the impact of the buffer transistor design on displacement damage and total ionizing dose response is investigated.

Investigating Pulsed X-ray Induced SEE in Analog Microelectronic Devices

We investigate analog single event transient (ASET) generation in an LM124 operational amplifier using focused pulsed x-rays and 800 nm femtosecond laser pulses. We report improvements that have been made to the pulsed x-ray experimental apparatus which include normal incidence geometry and a high speed x-ray chopper that allows us to reduce the pulse repetition frequency of the synchrotron derived x-ray pulse train. The addition of the chopper allows us to measure ASETs that have long relaxation times. We show that ASETs can be generated through metallization on the LM124, and that for equivalent pulse energy incident on the part, the x-ray response from areas covered by metal (and inaccessible to the laser) are different than the x-ray response from areas with no metallization, i.e. “metal-free”. We use the laser pulses to generate ASETs at the same metal-free locations of x-ray induced ASETs. The shapes of the ASETs generated by the two methods are compared. We use the differences seen from the two generation methods to estimate the charge generation/collection produced by the pulsed x-rays and then estimate what LET this would correspond to for heavy ions. This work shows that pulsed x-rays can be used to characterize analog devices for single event effects.

Study and Modeling of the Impact of TID on the ATREE Response in LM124 Operational Amplifier

Shapes of ATREEs (Analog Transient Radiation Effects on Electronics) in a bipolar integrated circuit change with exposure to Total Ionizing Dose (TID) radiation. The impact of TID on ATREEs is investigated in the LM124 operational amplifier (opamp) from three different manufacturers. Significant variations are observed on the ATREE responsesfrom different manufacturers. The ATREEs are produced by pulsed X-ray experiments. ASET laser mappings are performed to highlight the sensitive bipolar transistors, explaining the ATREE phenomena variations from one manufacturer to another one. ATREE modeling results are presented using a previously developed simulation tool. A good agreement is observed between experimental ATREE responses and model outputs whatever the TID level, the prompt dose level, the amplifier configuration and the device manufacturer.

Modeling and Investigations on TID-ASETs Synergistic Effect in LM124 Operational Amplifier From Three Different Manufacturers

The synergistic effect between Total Ionizing Dose (TID) and Analog Single Event Transient (ASET) in LM124 operational amplifiers (opamps) from three different manufacturers is investigated. This effect is clearly identified on only two manufacturers by three, highlighting manufacturer dependent. In fact, significant variations were observed on both the TID sensitivity and the ASET response of LM124 devices from different manufacturers. Hypotheses are made on the cause of the differences observed. A previously developed ASET simulation tool is used to model the transient response. The effects of TID on devices are taken into account in the model by injecting the variations of key electrical parameters obtained during Co60 irradiation. An excellent agreement is observed between the experimental responses and the model outputs, independently of the TID level, the bias configuration and the manufacturer of the device.

Study of Synergism Effect Between TID and ATREE on the Response of the LM124 Operational Amplifier

The Synergistic effect between Total Ionizing Dose (TID) and Analog Transient Radiation Effects in Electronics (ATREE) in an operational amplifier (LM124) is investigated. A predictive methodology, based on a previously developed ATREEs simulation tool, is used to model the synergistic phenomena. This phenomenon is simulated for the first time and the duration of the ATREEs' is found to be identical to those measured experimentally. ATREEs induced by high dose-rate X-ray pulses are investigated using a flash X-ray facility. The ATREEs induced in the LM124 operational amplifier configured in three different bias configurations are investigated and simulated.

Impact of Switched Dose-Rate Irradiation on the Response of the LM124 Operational Amplifier to Pulsed X-Rays

The Synergistic effect between TID and ATREEs (Analog Transient Radiation Effects on Electronics) in an operational amplifier (opamp) (LM124) is investigated for three different bias configurations. An accelerated irradiation technique is used to study these synergistic effects. The impact of TID on ATREEs is found to be identical regardless of whether the irradiation is performed at low dose rate or whether the dose rate is switched from high to low using the Dose Rate Switching (DRS) technique. The correlation between the deviations of the opamp's electrical parameters and the changes of ATREE widths is clearly established.

Investigation and Analysis of LM124 Bipolar Linear Circuitry Response Phenomenon in Pulsed X-Ray Environment

Analog Transient Radiation Effects in Electronics (ATREE) induced by high dose-rate X-ray pulses are investigated using a flash X-ray facility. The ATREEs induced in a LM124 operational amplifier configured in three different bias configurations are investigated. A predictive methodology, based upon a previously developed ASET simulation tool, is used to model the ATREE phenomena. A semiempirical physical model is used to perform the correlation between the duration of the parasitic pulse signal induced in the LM124 and an equivalent value of the high dose-rate X-ray pulse level.

Modification of the LM124 Single Event Transients by Load Resistors

The influence of a load resistor on the shape of the single event transients was investigated in the LM124 operational amplifier by means of laser tests. These experiments indicated that, as a general rule, load resistors modify the size of the transients. SPICE simulations helped to understand the reasons of this behavior and showed that the distortion is related to the necessity of providing or absorbing current from the load resistor, which forces the amplifier to modify its operation point. Finally, load effects were successfully used to explain the distortion of single event transients in typical feed-back networks and the results were used to explain experimental data reported elsewhere.

Probing With Heavy Ions the SET Sensitivity of Linear Devices

This paper reports on SET heavy ion data used to estimate the range effects and depth location of sensitive structures of the LM124 operational amplifier. These data are correlated with laser measurements and provide experimental insight into the SET test recommendations and prediction rate methodology.

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.

Comparison of single-event transients induced in an operational amplifier (LM124) by pulsed laser light and a broad beam of heavy ions

A comparison of single-event transients (SETs) from heavy-ion and pulsed-laser irradiation of the LM124 operational amplifier shows good agreement for different voltage configurations. The agreement is illustrated by comparing both individual transient shapes and plots of transient amplitude versus width.

2003 IEEE Nuclear and Space Radiation Effects Conference utstanding Conference Paper Award

The recipients of the 2003 IEEE NSREC Outstanding Paper Award are Dale McMorrow, William Lotshaw, Joseph Melinger, Steve Buchner, Younes Boulghassoul, Lloyd Massengill, and Ron Pease for their paper entitled "Three-Dimensional Mapping of Single Event Effects Using Two Photon Absorption." This work describes the application of a new technique, two-photon absorption, to examine single event effects in a semiconductor device. In two-photon absorption, a laser is used in which the wavelength is chosen to be lower than the bandgap of the semiconductor so that no carriers are generated at low intensities. However, at high intensities, the material can absorb two photons simultaneously to generate a single electron-hole pair. This allows tight control over where the carrier generation occurs, and provides for charge injection at any depth within the device structure permitting three-dimensional mapping of single event effects sensitivity of the device. In this work, the technique is developed and an example map is shown for single event transients in an LM124 operational amplifier.

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.

Analytical model for proton radiation effects in bipolar devices

The input bias current response of LM124 operational amplifiers to proton irradiation is shown to correlate with the response of identical part types exposed to neutrons and, subsequently, irradiated with X-rays. Moreover, the bias current responses to proton and combined neutron/X-ray exposures are more sublinear than the sum of neutron and X-ray radiation responses measured independently. These data indicate that the ionization defects introduced by proton irradiation moderate the effects of proton-induced displacement damage in the critical bipolar transistors within the LM124. An analytical model is presented that characterizes the various mechanisms of proton radiation effects in bipolar transistors, including the combined effects of oxide charge and bulk traps on carrier recombination. Prototype transistor responses simulated using the model show good correlation with the sublinear characteristics observed in the experimental data. Furthermore, the model is used to assess whether a bipolar junction transistor (BJT), designed with specific structural characteristics and operating in a proton-rich environment, will suffer the most degradation from damage caused by bulk displacement, ionization damage, or a combination of both.

Circuit modeling of the LM124 operational amplifier for analog single-event transient analysis

This work presents the development of a transistor-level circuit model of the LM124 operational amplifier specifically engineered and calibrated for analog single-event transient (ASET) computer simulations. The techniques presented rely heavily on datasheet specifications for electrical parameterization and experimental laser probing for dc and transient calibration. The resulting circuit model proves to be suitable for broad-beam SET predictions and fault diagnostics for space applications.

Effect of amplifier parameters on single-event transients in an inverting operational amplifier

Laser data and simulation tools are combined to investigate the single-event transient response of the LM124 operational amplifier. The effect of the bandwidth and gain on transients originating in different stages in the operational amplifier is studied. We found that the single-event transient response of the LM124 operational amplifier in an inverting configuration was dependent on the bandwidth of the amplifier, the gain, and on the values of the resistors used to program the gain of the amplifier. We show the results of simulations which illustrate how these changes impact the single-event transient response of the amplifier. An analysis of the results suggests which properties of an operational amplifier will provide a better single-event transient response.

Proton radiation response mechanisms in bipolar analog circuits

The experimental data presented in this paper indicate that the doping and geometry of critical transistors are the primary factors that affect the proton responses of the LM124 and LM148 operational amplifiers. The data also reveal that the electrical responses of these circuits and their input transistors to the combined effects of displacement damage and defects introduced by ionizing radiation are nonlinear. Analysis, supported by device simulation, shows that shifts in device parameters (surface potentials, carrier concentrations, etc.) caused by the buildup of oxide and interfacial defects affect the recombination rate due to traps resulting from displacement damage in the bulk silicon. This nonlinearity complicates the analysis of proton radiation effects and can have a significant impact on the qualification of analog parts for use in space environments.

Origins of total-dose response variability in linear bipolar microcircuits

LM111 voltage comparators exhibit a wide range of total-dose-induced degradation. Simulations show this variability may be a natural consequence of the low base doping of the substrate PNP (SPNP) input transistors. Low base doping increases the SPNPs collector to base breakdown voltage, current gain, and sensitivity to small fluctuations in the radiation-induced oxide defect densities. The build-up of oxide trapped charge (N/sub OT/) and interface traps (N/sub IT/) is shown to be a function of pre-irradiation bakes. Experimental data indicate that, despite its structural similarities to the LM111, irradiated input transistors of the LM124 operational amplifier do not exhibit the same sensitivity to variations in pre-irradiation thermal cycles. Further disparities in LM111 and LM124 responses may result from a difference in the oxide defect build-up in the two part types. Variations in processing, packaging, and circuit effects are suggested as potential explanations.

Analysis of single-event transients in analog circuits

A new methodology for understanding single-event transient (SET) phenomena in analog circuits is described. Device and circuit simulation techniques are coupled in order to reproduce experimental data obtained from the National Semiconductor LM124 operational amplifier and to determine the most sensitive parts of the integrated circuit. Experimental data obtained at the Physical Nuclear Institute from a low-power voltage regulator that uses the LM124 are also used to illustrate the method.