Semiconductor Device Models Constructed Using Simple Elements and Auxiliary Dynamics
Abstract not provided.
Publications
A Numerical Compact Photocurrent Model and its Implementation via Xyce-PyMi
Abstract not provided.
Radiation and Self Heating Effects in Hetero-Junction Bipolar Transistors (FY2019 L2 MileStone 6723 Report)
Hetero-Junction Bipolar Transistors (HBT) have several advantages over Silicon Bipolar Junction Transistors (BJT) in radiation environments. One advantage is an intrinsic hardness to displacement damage causing radiation. The generally smaller size of HBTs compared to BJTs also means that less photocurrent is generated by these devices. A disadvantage of the smaller size is less ability to dissipate heat due to smaller surface areas and contacts. This report describes simulations intended to study the initial heating of HBT transistors due to ionizing radiation events and the subsequent heating caused by feedback in the devices when responding to these events.
Radiation and Self Heating Effects in Hetero-Junction Bipolar Transistors
Abstract not provided.
Understanding the Implications of a LINAC?s Microstructure on Transient Photocurrent Models
Abstract not provided.
Understanding the Implications of a LINAC's Microstructure on Devices and Photocurrent Models
IEEE Transactions on Nuclear Science
The effect of a linear accelerator's (LINAC's) microstructure (i.e., train of narrow pulses) on devices and the associated transient photocurrent models are investigated. The data indicate that the photocurrent response of Si-based RF bipolar junction transistors and RF p-i-n diodes is considerably higher when taking into account the microstructure effects. Similarly, the response of diamond, SiO2, and GaAs photoconductive detectors (standard radiation diagnostics) is higher when taking into account the microstructure. This has obvious hardness assurance implications when assessing the transient response of devices because the measured photocurrent and dose rate levels could be underestimated if microstructure effects are not captured. Indeed, the rate the energy is deposited in a material during the microstructure peaks is much higher than the filtered rate which is traditionally measured. In addition, photocurrent models developed with filtered LINAC data may be inherently inaccurate if a device is able to respond to the microstructure.
Understanding the Implications of a LINAC?s Microstructure on Photocurrent Modeling
Abstract not provided.
Circuit and Device Simulation Support for Design and Qualification of Parts and Systems
Abstract not provided.
Test Simulation of Neutron Damage to Electronic Components using Accelerator Facilities
Abstract not provided.
High Accuracy Transistor Compact Model Calibrations
Typically, transistors are modeled by the application of calibrated nominal and range models. These models consists of differing parameter values that describe the location and the upper and lower limits of a distribution of some transistor characteristic such as current capacity. Correspond- ingly, when using this approach, high degrees of accuracy of the transistor models are not expected since the set of models is a surrogate for a statistical description of the devices. The use of these types of models describes expected performances considering the extremes of process or transistor deviations. In contrast, circuits that have very stringent accuracy requirements require modeling techniques with higher accuracy. Since these accurate models have low error in transistor descriptions, these models can be used to describe part to part variations as well as an accurate description of a single circuit instance. Thus, models that meet these stipulations also enable the calculation of quantifi- cation of margins with respect to a functional threshold and uncertainties in these margins. Given this need, new model high accuracy calibration techniques for bipolar junction transis- tors have been developed and are described in this report.
Precision circuit calculations in hostile environments
Sandia journal manuscript; Not yet accepted for publication
Sensing and calculating electronic systems with stringent accuracy requirements use internal standard voltages for references. Conceptually, this is related to using some unit measurement for counting any quantity. The high precision electronic components used in systems in the nation’s stockpile also make use of these standard voltages. The need for stable voltage references has been long-standing in the overall electronics industry. For many applications, the most pressing need is for stability of a reference voltage as the circuit temperature varies. Typical circuit components have temperature coefficients for their operational characteristics that are given in some delta per degree centigrade and these coefficients can be either positive or negative. Thus, it is natural to consider building a circuit out of components that have complementary temperature coefficients so that the operating characteristics of the circuit have a net zero temperature coefficient. This is the fundamental basis of precision voltage reference (PVR) circuit operation and it is straightforward to extend this type of stabilization to reduce shifts caused by hostile environment radiation.
A new time-dependent analytic compact model for radiation-induced photocurrent in epitaxial structures
Abstract not provided.
A new time-dependent analytic compact model for radiation-induced photocurrent in epitaxial structures
Abstract not provided.
A new time-dependent analytic compact model for radiation-induced photocurrent in epitaxial structures
Abstract not provided.
A new time-dependent analytic model for radiation-induced photocurrent in finite 1D epitaxial diodes
Photocurrent generated by ionizing radiation represents a threat to microelectronics in radiation environments. Circuit simulation tools such as SPICE [1] can be used to analyze these threats, and typically rely on compact models for individual electrical components such as transistors and diodes. Compact models consist of a handful of differential and/or algebraic equations, and are derived by making simplifying assumptions to any of the many semiconductor transport equations. Historically, many photocurrent compact models have suffered from accuracy issues due to the use of qualitative approximation, rather than mathematically correct solutions to the ambipolar diffusion equation. A practical consequence of this inaccuracy is that a given model calibration is trustworthy over only a narrow range of operating conditions. This report describes work to produce improved compact models for photocurrent. Specifically, an analytic model is developed for epitaxial diode structures that have a highly doped subcollector. The analytic model is compared with both numerical TCAD calculations, as well as the compact model described in reference [2]. The new analytic model compares well against TCAD over a wide range of operating conditions, and is shown to be superior to the compact model from reference [2].
A physics-based device model of transient neutron damage in bipolar junction transistors
IEEE Transactions on Nuclear Science
For the purpose of simulating the effects of neutron radiation damage on bipolar circuit performance, a bipolar junction transistor (BJT) compact model incorporating displacement damage effects and rapid annealing has been developed. A physics-based approach is used to model displacement damage effects, and this modeling approach is implemented as an augmentation to the Gummel-Poon BJT model. The model is presented and implemented in the Xyce circuit simulator, and is shown to agree well with experiments and TCAD simulation, and is shown to be superior to a previous compact modeling approach. © 2010 IEEE.
A Physics-based Device Model of Transient Neutron Damage in Bipolar Junction Transistors
IEEE Transactions on Nuclear Science
Abstract not provided.
A Physics-based Device Model of Transient Neutron Damage in Bipolar Junction Transistors
IEEE Transactions on Nuclear Science
Abstract not provided.
Test Simulation of Neutron Damage to Electronic Components using Accelerator Facilities
Abstract not provided.
Test Simulation of Neutron Damage to Electronic Components and Circuits using Accelerator Facilities
Abstract not provided.
Effects of Neutron and Electron Beam Pre-irradiation on Photocurrent
Abstract not provided.
Verification, validation and quantification of margins and uncertainties for electrical systems
Abstract not provided.
Radiation-induced traps in silicone bipolar transistors
Abstract not provided.
Radiation aging of stockpile and space-based microelectronics
This report describes an LDRD-supported experimental-theoretical collaboration on the enhanced low-dose-rate sensitivity (ELDRS) problem. The experimental work led to a method for elimination of ELDRS, and the theoretical work led to a suite of bimolecular mechanisms that explain ELDRS and is in good agreement with various ELDRS experiments. The model shows that the radiation effects are linear in the limit of very low dose rates. In this limit, the regime of most concern, the model provides a good estimate of the worst-case effects of low dose rate ionizing radiation.
Mechanisms for radiation dose-rate sensitivity of bipolar transistors
Mechanisms for enhanced low-dose-rate sensitivity are described. In these mechanisms, bimolecular reactions dominate the kinetics at high dose rates thereby causing a sub-linear dependence on total dose, and this leads to a dose-rate dependence. These bimolecular mechanisms include electron-hole recombination, hydrogen recapture at hydrogen source sites, and hydrogen dimerization to form hydrogen molecules. The essence of each of these mechanisms is the dominance of the bimolecular reactions over the radiolysis reaction at high dose rates. However, at low dose rates, the radiolysis reaction dominates leading to a maximum effect of the radiation.
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