ABACUS - Assembly of Basic Applications for Coordinated Understanding of Semiconductors
Recitation Abstracts
ABACUS Overview and Crystal Structures
December 1, 2021, 6:00 PM - 6:45 PM EST and April 11, 2022, 10:00 AM - 10:45 AM EDT
In the first session, Dr. Klimeck will briefly overview ABACUS and demonstrate the crystal viewer tool. With crystal viewer, students can start with the visualization of a standard Silicon text book unit cell, then expand the view to a larger crystal and immerse themselves into the various directional symmetries with activities such as viewing Miller planes and counting the number of bonds on such surfaces.
December 8, 2021, 6:00 PM - 6:45 PM EST and April 18, 2022, 10:00 AM - 10:45 AM EDT
In the second session, Dr. Klimeck will give a brief overview of ABACUS and demonstrate the PN Junction Lab. With the PN Junction Lab, students can explore band edge diagrams and charge distributions as a function of bias. They can see how the bands move and how the depletion region narrows and widens. Students can change the doping levels and explore shallow versus wide junctions. Learners with a deeper interest can dive into the effects of minority carrier relaxation times and resistive behavior in realistic devices. The PN Junction Lab is powered “under the hood” with an industrial strength simulation engine that was designed and used at Bell Labs to model and produce a variety of different electronic devices.
December 15, 2021, 6:00 PM - 6:45 PM EST and April 27, 2022, 10:00 AM - 10:45 AM EDT
In the third session, Dr. Klimeck will give a brief overview of ABACUS and demonstrate several bandstructure tools. With these, students can explore the Standard Periodic Potential aka Kronig-Penney model as well as bandstructure formation by transmission through finite barriers. They can change barrier heights or shapes and gain a “feeling” for the resulting shapes and effective masses of the bands. The more sophisticated bandstructure lab enables students to model standard bulk materials such as Si or GaAs in a sophisticated Tight Binding model used in NEMO5. Effects of various strain configurations can be modeled and visualized. The tool can also model the bandstructure of modern nanowires. Some of these tools are powered by NEMO5 which is now being used to design nanometer scaled transistors in industry.
Drift-Diffusion-Lab with Bias and Light
January 12, 2022, 6:00 PM - 6:45 PM EST and May 2, 2022, 10:00 AM - 10:45 AM EDT
In the fourth session, Dr. Gerhard Klimeck will give a brief overview of ABACUS and demonstrate the Drift-Diffusion-Lab. Students can experiment with a semiconductor slab under bias and/or light illumination. They can explore how illumination from the top of an intrinsic semiconductor increases the overall current and separates the hole and electron distribution across the device. They can change the light intensity and the location of the illumination. Different materials such as Si, SiGe, and GaAs can be explored. Detailed parameters such as minority carrier lifetimes or surface recombination times can be modified in numerical experiments to explore the concepts. Drift-Diffusion-Lab is powered by the industrial tool PADRE which was used at Bell Labs to design transistors.
January 19, 2022, 6:00 PM - 6:45 PM EST and May 11, 2022, 10:00 AM - 10:45 AM EDT
In the fifth session, Dr. Klimeck will give a brief overview of ABACUS and demonstrate the Bipolar-Junction-Transistor-Lab. Students can experiment with npn and pnp BJTs in ideal textbook 1D geometries as well as realistic 2D geometries. Different experiments with variations in doping profiles, layer thicknesses, and material systems (Si, Ge, GaAs) can be explored. Bipolar-Junction-Transistor-Lab computes internal device quantities such as charge profiles, band edge profiles, and recombination rates at equilibrium and applied bias throughout the length of the device. It also computes the terminal currents in the form of a Gummel plot as well as common emitter output current. The transistor beta is explicitly computed as a function of collector current. Students can also explore intricate consequences of different minority carrier lifetimes. Bipolar-Junction-Transistor-Lab is powered by the industrial tool PADRE which was used at Bell Labs to design transistors.
January 26, 2022, 6:00 PM - 6:45 PM EST and May 16, 2022, 10:00 AM - 10:45 AM EDT
In the sixth session, Dr. Gerhard Klimeck will give a brief overview of ABACUS and demonstrate the MOS Capacitor Lab. Students can experiment with the fundamental component of a MOSfet that is any computer chip. Students can explore the high and low frequency response of n-type and p-type MOS capacitors as a function of doping and structural parameters such as oxide thickness, dielectric constants, and semiconductor thickness. Students can also explore sophisticated effects such as surface charges, oxide charges and monitory carrier lifetimes. MOS-Capacitor-Lab is powered by the industrial tool PADRE which was used at Bell Labs to design transistors.
February 2, 2022, 6:00 PM - 6:45 PM EST and May 25, 2022, 10:00 AM - 10:45 AM EDT
In the seventh session, Dr. Klimeck will give a brief overview of ABACUS and demonstrate the MOSFET Lab. Students can experiment with the classical scaling of a traditional 2D MOSFET. Shortening the gate length will deteriorate the device performance and raise the leakage current. Students can also explore double gate MOSFETs which will have improved performance compared to the standard 2D MOSFET. Various effects due to oxide thickness, gate workfunction, doping and doping profiles can be examined. Also material properties such as minority carrier lifetimes can be explored. MOSFET-Lab is powered by the industrial tool PADRE which was used at Bell Labs to design transistors.