Combining n-MOS Charge Sensing with p-MOS Silicon Hole Double Quantum Dots in a CMOS platform.

Holes in silicon quantum dots are receiving attention due to their potential as fast, tunable, and scalable qubits in semiconductor quantum circuits. Despite this, challenges remain in this material system including difficulties using charge sensing to determine the number of holes in a quantum dot, and in controlling the coupling between adjacent quantum dots. We address these problems by fabricating an ambipolar complementary metal-oxide-semiconductor (CMOS) device using multilayer palladium gates. The device consists of an electron charge sensor adjacent to a hole double quantum dot. We demonstrate control of the spin state via electric dipole spin resonance. We achieve smooth control of the interdot coupling rate over 1 order of magnitude and use the charge sensor to perform spin-to-charge conversion to measure the hole singlet-triplet relaxation time of 11 µs for a known hole occupation. These results provide a path toward improving the quality and controllability of hole spin-qubits.

Multilevel States of Nano-Electromechanical Switch for a PUF-Based Security Device.

A nano-electromechanical (NEM) switch using multilevel states based on the high security physical unclonable function (PUF) is proposed and experimentally demonstrated. Using the asymmetric random stiction of a silicon nanowire (SiNW), the conventional binary state is simply expanded to a quaternary-state encryption key without increasing chip area. The multiple states are determined by the asymmetrically bent direction and stiction of the SiNW. The experimental results show that the fabricated NEM-PUF with multistates retains unique, random, and robust characteristics, while the key capacity is doubled, even with the same array size footprint.

Ferromagnetic nanoparticle-embedded hybrid nanogenerator for harvesting omnidirectional vibration energy.

A new form of generator known as the triboelectric nanogenerator (TENG) has recently been suggested as a simple and low-cost solution to scavenge ambient mechanical energy. Although there have been substantial advances in TENGs over the past few years, the power efficiency of TENGs must be enhanced further before they can be practically applied. In the present study, we report a ferromagnetic nanoparticle-embedded hybrid nanogenerator (FHNG) which operates based on both triboelectricity and electromagnetic induction. A TENG and an electromagnetic generator (EMG) efficiently cooperate to generate electrical energy from the same motion, i.e., the vibration of a synthesized nanoparticle. A surface-functionalized ferric oxide nanoparticle, which has strong ferromagnetism and high triboelectricity, was produced by a simple surface-coating process. The measured electrical characteristics revealed that the output voltage of both the TENG and the EMG components increased by approximately 50 times and by twofold, respectively, after the surface functionalization step. Moreover, when constant vibration of 3 Hz is applied to the fabricated FHNG, the TENG and EMG components correspondingly generated output power of 133.2 µW at a load resistance of 100 MΩ and 6.5 µW at a load resistance of 200 Ω. The output power per unit mass from the FHNG is greater than that according to the arithmetic sum of the individual TENG and EMG components, demonstrating synergy between the two components. Furthermore, the device can generate stable output under various vibration directions, amplitudes, and frequencies due to the fluid-like characteristics of the powder. The packaged structure also securely protects the device from external humidity and dust. Connected to a rationally designed power management circuit, a digital clock was turned on solely by the fabricated FHNG.

On-Chip Curing by Microwave for Long Term Usage of Electronic Devices in Harsh Environments.

Microwave-induced thermal curing is demonstrated to improve the reliability and to prolong the lifetime of chips containing nanoscale electron devices. A film containing graphite powder with high microwave absorbing efficiency was fabricated at low cost. The film is flexible, bendable, foldable, and attachable to a chip. A commercial off-the-shelf chip and a representative 3-dimensional (3D) metal-oxide-semiconductor field-effect transistor (MOSFET), known as FinFET, were utilized to verify the curing behaviors of the microwave-induced heat treatment. The heat effectively cured not only total ionizing dose (TID) damage from the external environment, but also internal electrical stress such as hot-carrier injection (HCI), which are representative sources of damages in MOSFET insulators. Then, the characteristics of the pre- and post-curing electron devices are investigated using electrical measurements and numerical simulations.