Development of low thermal budget Si epitaxy and high-k/ metal gate stack for atomically precise electronic devices
Abstract not provided.
Publications
Modeling and Assessment of Atomic Precision Advanced Manufacturing (APAM) Enabled Vertical Tunneling Field Effect Transistor
International Conference on Simulation of Semiconductor Processes and Devices, SISPAD
The atomic precision advanced manufacturing (APAM) enabled vertical tunneling field effect transistor (TFET) presents a new opportunity in microelectronics thanks to the use of ultra-high doping and atomically abrupt doping profiles. We present modeling and assessment of the APAM TFET using TCAD Charon simulation. First, we show, through a combination of simulation and experiment, that we can achieve good control of the gated channel on top of a phosphorus layer made using APAM, an essential part of the APAM TFET. Then, we present simulation results of a preliminary APAM TFET that predict transistor-like current-voltage response despite low device performance caused by using large geometry dimensions. Future device simulations will be needed to optimize geometry and doping to guide device design for achieving superior device performance.
Leveraging Spin-Orbit Coupling in Ge/SiGe Heterostructures for Quantum Information Transfer
Hole spin qubits confined to lithographically - defined lateral quantum dots in Ge/SiGe heterostructures show great promise. On reason for this is the intrinsic spin - orbit coupling that allows all - electric control of the qubit. That same feature can be exploited as a coupling mechanism to coherently link spin qubits to a photon field in a superconducting resonator, which could, in principle, be used as a quantum bus to distribute quantum information. The work reported here advances the knowledge and technology required for such a demonstration. We discuss the device fabrication and characterization of different quantum dot designs and the demonstration of single hole occupation in multiple devices. Superconductor resonators fabricated using an outside vendor were found to have adequate performance and a path toward flip-chip integration with quantum devices is discussed. The results of an optical study exploring aspects of using implanted Ga as quantum memory in a Ge system are presented.
FAIR DEAL Grand Challenge Overview
While it is likely practically a bad idea to shrink a transistor to the size of an atom, there is no arguing that it would be fantastic to have atomic-scale control over every aspect of a transistor – a kind of crystal ball to understand and evaluate new ideas. This project showed that it was possible to take a niche technique used to place dopants in silicon with atomic precision and apply it broadly to study opportunities and limitations in microelectronics. In addition, it laid the foundation to attaining atomic-scale control in semiconductor manufacturing more broadly.
Modeling and Assessment of Atomic Precision Advanced Manufacturing (APAM) Enabled Vertical Tunneling Field Effect Transistor
Abstract not provided.
Path towards a vertical TFET enabled by atomic precision advanced manufacturing
Abstract not provided.
Room Temperature Operation of Donor-Based Atomically Precise Devices
Abstract not provided.
Room Temperature Operation of Donor-Based Atomically Precise Devices
Abstract not provided.
Modeling assisted room temperature operation of atomic precision advanced manufacturing devices
International Conference on Simulation of Semiconductor Processes and Devices, SISPAD
One big challenge of the emerging atomic precision advanced manufacturing (APAM) technology for microelectronics application is to realize APAM devices that operate at room temperature (RT). We demonstrate that semiclassical technology computer aided design (TCAD) device simulation tool can be employed to understand current leakage and improve APAM device design for RT operation. To establish the applicability of semiclassical simulation, we first show that a semiclassical impurity scattering model with the Fermi-Dirac statistics can explain the very low mobility in APAM devices quite well; we also show semiclassical TCAD reproduces measured sheet resistances when proper mobility values are used. We then apply semiclassical TCAD to simulate current leakage in realistic APAM wires. With insights from modeling, we were able to improve device design, fabricate Hall bars, and demonstrate RT operation for the very first time.
Modeling Assisted Room Temperature Operation of Atomic Precision Advanced Manufacturing Devices
Abstract not provided.
Low thermal budget high-k/metal surface gate for buried donor-based devices
JPhys Materials
Atomic precision advanced manufacturing (APAM) offers creation of donor devices in an atomically thin layer doped beyond the solid solubility limit, enabling unique device physics. This presents an opportunity to use APAM as a pathfinding platform to investigate digital electronics at the atomic limit. Scaling to smaller transistors is increasingly difficult and expensive, necessitating the investigation of alternative fabrication paths that extend to the atomic scale. APAM donor devices can be created using a scanning tunneling microscope (STM). However, these devices are not currently compatible with industry standard fabrication processes. There exists a tradeoff between low thermal budget (LT) processes to limit dopant diffusion and high thermal budget (HT) processes to grow defect-free layers of epitaxial Si and gate oxide. To this end, we have developed an LT epitaxial Si cap and LT deposited Al2O3 gate oxide integrated with an atomically precise single-electron transistor (SET) that we use as an electrometer to characterize the quality of the gate stack. The surface-gated SET exhibits the expected Coulomb blockade behavior. However, the gate’s leverage over the SET is limited by defects in the layers above the SET, including interfaces between the Si and oxide, and structural and chemical defects in the Si cap. We propose a more sophisticated gate stack and process flow that is predicted to improve performance in future atomic precision devices.
Theory of spin-orbit mediated hole spin-photon coupling in lateral Ge/SiGe quantum dots
Abstract not provided.
Development of a high-k gate stack for atomic-precision advanced manufacturing
Abstract not provided.
Modeling Assisted Atomic Precision Advanced Manufacturing (APAM) Towards Room Temperature Operation
Abstract not provided.
Modeling assisted APAM towards room temperature operation
Abstract not provided.
Designer quantum materials
Quantum materials have long promised to revolutionize everything from energy transmission (high temperature superconductors) to both quantum and classical information systems (topological materials). However, their discovery and application has proceeded in an Edisonian fashion due to both an incomplete theoretical understanding and the difficulty of growing and purifying new materials. This project leverages Sandia's unique atomic precision advanced manufacturing (APAM) capability to design small-scale tunable arrays (designer materials) made of donors in silicon. Their low-energy electronic behavior can mimic quantum materials, and can be tuned by changing the fabrication parameters for the array, thereby enabling the discovery of materials systems which can't yet be synthesized. In this report, we detail three key advances we have made towards development of designer quantum materials. First are advances both in APAM technique and underlying mechanisms required to realize high-yielding donor arrays. Second is the first-ever observation of distinct phases in this material system, manifest in disordered 2D sheets of donors. Finally are advances in modeling the electronic structure of donor clusters and regular structures incorporating them, critical to understanding whether an array is expected to show interesting physics. Combined, these establish the baseline knowledge required to manifest the strongly-correlated phases of the Mott-Hubbard model in donor arrays, the first step to deploying APAM donor arrays as analogues of quantum materials.
Surface gated atomically precise single electron Islands
Abstract not provided.
Modeling Transport in Phosphorus δ-Doped Silicon Tunnel Junctions
Abstract not provided.
Holes in germanium quantum wells and their potential applications in quantum computing
Abstract not provided.
Fabrication and Measurement of Actomically Precise Single Electron Islands
Abstract not provided.
Fabrication and programming of nanomagnet arrays for nanoscale magnetic field synthesis
Abstract not provided.
Modeling transport in phosphorus δ-doped silicon tunnel junctions
Abstract not provided.
Integrated devices made using atomic precision advanced manufacturing
Abstract not provided.
Engineering Spin-Orbit Interaction in Silicon
Abstract not provided.
Designing Nanomagnet Arrays for an Engineered Spin-Orbit Gap in Si
Abstract not provided.
Results 1–25 of 49