Jiayi Huang

A novel approach to quantitative determination of charge trapping near channel/drain edge in MOSFETs

Abstract In this letter, we report a novel approach to quantitative determination of charge trapping near the channel/drain edge caused by electrical stress. The approach is based on gate-controlled-diode (GCD) measurement. By measuring the GCD drain current in the band-to-band tunneling regime and using the formula developed in this work, the change of the Si surface field resulting from the charge trapping can be calculated instantly, and then the charge trapping is determined quantitatively. It is found that the stress-time dependence of both the surface field change and the charge trapping follow a power law.

Characterization of interface degradation in deep submicron MOSFETs by gate-controlled-diode measurement

Abstract The gate-controlled-diode (GCD) characteristic of a deep submicron MOSFET is changed dramatically following a Fowler–Nordheim (FN) injection. The changes can be explained by the trap generation on the Si surface close to the channel/drain edge and the interface trap generation in the channel region. By examining the change in the reverse drain current under accumulation and inversion in the GCD measurements, the information of trap generation in the surface region close to the channel/drain edge is obtained (note that the trap generation in this region could be different from that in other interface regions); and by measuring the reverse drain current under depletion, the interface trap generation in the channel region is obtained.

A quantitative study of the relationship between the oxide charge trapping over the drain extension and the off-state drain leakage current

In this letter, we report an approach to quantitative study of the relationship between the oxide charge trapping over the drain extension due to electrical stress and the off-state drain leakage current. It is found that positive charge trapping over the drain extension leads to a significant increase in the off-state drain current if the edge direct tunneling (EDT) is dominant in the drain current but in contrast, it leads to a reduction in the drain current if the band-to-band tunneling in the Si surface is dominant. A quantitative relationship between the charge trapping and the off-state drain leakage current in the EDT regime is established. From the measurement of the off-state current in the EDT regime, the charge trapping can be determined by using the approach developed in this study.

Gate oxide thickness dependence of edge charge trapping in NMOS transistors caused by charge injection under constant-current stress

This brief reports a study of charge injection-induced edge charge trapping in the gate oxide overlapping the drain extension which has an impact on the drain leakage current. The edge charge trapping is determined for the gate oxide thickness of 6.5, 3.9, and 2.0 nm by using a simple approach to analyze the change of the band-to-band tunneling current measured with a three-terminal gate-controlled-diode configuration. The edge charge trapping has a strong dependence on the gate oxide thickness, and it is different from the charge trapping in the oxide over the channel. A plausible explanation for both the oxide thickness dependence of the edge charge trapping and the difference between the edge charge trapping and the charge trapping over the channel is presented.

NEMS actuator driven by electrostatic and optical force with nano-scale resolution

We experimentally demonstrate a silicon nano-wire actuator with a nano-scale resolution and tunable actuation range. The nano-scale resolution is obtained through implementing different control regulations, including coarse tuning by the electrostatic force and precision tuning by the optical force. More specially, the optical force enabled silicon nano-wire actuator can break the classical NEMS 1/3 actuation range limit, extending the actuation range to an arbitrary limit in principle. This unique approach not only provides a simple, non-intrusive solution to the tunable air gap of NEMS devices, but also presents an ultra-sensitive optical read out of the mechanical motion.

A nanomachined tunable oscillator controlled by electrostatic and optical force

We develop a miniaturized electrostatically tunable optomechanical oscillator, whose frequencies can be electrostatically tuned by as much as 10%. By taking advantage of the optical and the electrical spring, the oscillator achieves a high tuning sensitivity without resorting to mechanical tension. Particularly, the high-Q optical cavity greatly enhances the system sensitivity, making it extremely sensitive to the motional signal, which is often overwhelmed by background noise.

Influence of nitrogen concentration in nitrided oxides on interface trap generation caused by Fowler-Nordheim injection

In this study, a novel technique, i.e. the direct-current current–voltage method is used to quantitatively examine the influence of nitrogen concentration in nitrided oxides on interface trap generation caused by Fowler–Nordheim injection. A power-law stress time dependence of interface trap generation is always observed. As the nitrogen concentration is increased, the exponent of the power law is reduced leading to a significant suppression of interface trap generation. However, no significant polarity dependence from the influence of nitrogen concentration is observed. These experimental findings are used to clarify the two models that have been proposed to explain the reduced degradation of nitrided oxides under electrical stress.

A dissipative self-sustained optomechanical resonator on a silicon chip

In this letter, we report the experimental demonstration of a dissipative self-sustained optomechanical resonator on a silicon chip by introducing dissipative optomechanical coupling between a vertically offset bus waveguide and a racetrack optical cavity. Different from conventional blue-detuning limited self-oscillation, the dissipative optomechanical resonator exhibits self-oscillation in the resonance and red detuning regime. The anti-damping effects of dissipative optomechanical coupling are validated by both numerical simulation and experimental results. The demonstration of the dissipative self-sustained optomechanical resonator with an extended working range has potential applications in optomechanical oscillation for on-chip signal modulation and processing.In this letter, we report the experimental demonstration of a dissipative self-sustained optomechanical resonator on a silicon chip by introducing dissipative optomechanical coupling between a vertically offset bus waveguide and a racetrack optical cavity. Different from conventional blue-detuning limited self-oscillation, the dissipative optomechanical resonator exhibits self-oscillation in the resonance and red detuning regime. The anti-damping effects of dissipative optomechanical coupling are validated by both numerical simulation and experimental results. The demonstration of the dissipative self-sustained optomechanical resonator with an extended working range has potential applications in optomechanical oscillation for on-chip signal modulation and processing.

A reconfigurable coupled optical resonators in photonic circuits for photon shutting

We demonstrate a novel way to control the coupling rate in coupled ring resonators by controlling the relative position of the nanowires between the two cavities to modulate the resonance frequencies. A new system is presented and experimental results show that by tuning the coupling rate, the coupled ring resonators can be stimulated at the same time due to the same resonance frequency. This study will provide new ways to manipulate coupled photonic cavities in silicon photonic circuits and benefit the development of coupled optical cavities to achieve advanced functions.

All optomechanical signal modulation in photonic circuits

This paper reports a novel all-optical light tracker by taking advantage of the optomechanical modulation. The optical force generated by a light can be used to control another light without relying on the traditional nonlinear material. Particularly, the all-optical modulation can transfer the information in a signal light into another tracking light without resorting to electro-optical converting. The novel all-optical modulation will have great potential use in on-chip signal processing.