Charge Collection Physical Modeling for Soft Error Rate Computational Simulation in Digital Circuits
This chapter describes a new computational approach for accurately modeling radiation-induced single-event transient current and charge collection at circuit level. This approach, called random-walk drift-diffusion (RWDD), is a fast Monte Carlo particle method based on a random-walk process that takes into account both diffusion and drift of carriers in a non-constant electric field both in space and time. After introducing the physical insights of the RWDD model, the chapter details the practical implementation of the method using an object-oriented programming language and its parallelization on graphical processing units. Besides, the capability of the approach to treat multiple node charge collection is presented. The chapter also details the coupling of the model either with an internal routine or with SPICE for circuit solving. Finally, the proposed approach is illustrated at device and circuit level, considering four different test vehicles in 65 nm technologies: a stand-alone transistor, a CMOS inverter, a SRAM cell and a flip-flop circuit. RWDD results are compared with data obtained from a full three-dimensional (3D) numerical approach (TCAD simulations) at transistor level. The importance of the circuit feedback on the charge-collection process is also demonstrated for devices connected to other circuit nodes.
Part of the book: Modeling and Simulation in Engineering Sciences
Susceptibility of Group-IV and III-V Semiconductor-Based Electronics to Atmospheric Neutrons Explored by Geant4 Numerical Simulations
New semiconductor materials are envisaged in numerous high-performance applications for which the expected device or circuit performances cannot be achieved with silicon. In this context of growing use of new and specific semiconductors, the question of their susceptibility to natural radiation, primarily to atmospheric neutrons, is posed for high-reliability-level application domains. This numerical simulation work precisely examines nuclear events resulting from the interaction of atmospheric neutrons at the terrestrial level with a target layer composed of various group-IV and III-V semiconductor materials including silicon, germanium, silicon carbide, carbon-diamond, gallium arsenide, and gallium nitride materials. Using extensive Geant4 simulations and in-depth data analysis, this study provides an accurate and fine comparison between the neutron interaction responses of these different semiconductors in terms of nuclear processes, recoil products, secondary ion production, and fragment energy distributions. Implications of these results on the rate of single-event transient effects at the device or circuit level are also discussed.
Part of the book: Numerical Simulations in Engineering and Science
Interactions between Terrestrial Cosmic-Ray Neutrons and III–V Compound Semiconductors
This work explores by numerical simulation the impact of high-energy atmospheric neutrons and their interactions with III–V binary compound semiconductors. The efforts have focused on eight III–V semiconductors: GaAs, AlAs, InP, InAs, GaSb, InSb, GaN, and GaP. For each material, extensive Geant4 numerical simulations have been performed considering a bulk target exposed to a neutron source emulating the atmospheric neutron spectrum at terrestrial level. Results emphasize in detail the reaction rates per type of reaction (elastic, inelastic, nonelastic) and offer a classification of all the neutron-induced secondary products as a function of their atomic number, kinetic energy, initial stopping power, and range. Implications for single-event effects (SEEs) are analyzed and discussed, notably in terms of energy and charge deposited in the bulk material and in the first nanometers of particle range with respect to the critical charge for modern complementary metal oxide semiconductor (CMOS) technologies.
Part of the book: Modeling and Simulation in Engineering
Radiation Response of Group-IV and III-V Semiconductors Subjected to D–D and D–T Fusion Neutrons View all chapters
This work focuses on the radiation response of Group IV (Si, Ge, SiC, diamond) and III-V (GaAs, GaN, GaP, GaSb, InAs, InP, InSb, AlAs) semiconductors subjected to D–D (2.45 MeV) and D–T (14 MeV) neutrons. The response of each material has been systematically investigated through a direct calculation using nuclear cross-section libraries, MCNP6, and Geant4 numerical simulations. For the semiconductor materials considered, we have investigated in detail the reaction rates per type of reaction (elastic, inelastic, and nonelastic) and proposed an exhaustive classification and counting of all the neutron-induced events and secondary products as a function of their nature and energy. Several metrics for quantifying the susceptibility of the related semiconductor-based electronics to neutron fusions have been finally considered and discussed.
Part of the book: New Advances in Semiconductors