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111.
112.
The NBTI degradation phenomenon and the role of hydrogen during NBT stress
are presented in this paper. It is found that PBT stress can recover a
fraction of Vth shift induced by NBTI. However, this recovery is
unstable. The original degradation reappears soon after reapplication of the NBT
stress condition. Hydrogen-related species play a key role during a device's NBT
degradation. Experimental results show that the diffusion species are
neutral, they repassivate Si dangling bond which is independent of the gate
voltage polarity. In addition to the diffusion towards gate oxide, hydrogen
diffusion to Si-substrate must be taken into account for it also has
important influence on device degradation during NBT stress. 相似文献
113.
In the GaN-based heterostructures, this paper reports that the strong electric
fields induced by polarization effects at the structure boundaries complicate the
electric--static equilibrium and the boundary conditions. The basic requirements of
electric--static equilibrium for the heterostructure systems are discussed first,
and it is deduced that in the application of the coupled Schr\"{o}dinger--Poisson
model to the heterostructures of electric--static equilibrium state, zero external
electric field guarantees the overall electric neutrality, and there is no need to
introduce the charge balance equation. Then the relation between the screening of
the polar charges in GaN-based heterostructures and the possible boundary conditions
of the Poisson equation is analysed, it is shown that the various boundary
conditions are equivalent to each other, and the surface charge, which can be used
in studying the screening of the polar charges, can be precisely solved even if only
the conduction band energy is correctly known at the surface. Finally, through the
calculations on an AlGaN/GaN heterostructure with typical structure parameters by
the coupled Schr\"{o}dinger--Poisson model under the various boundary conditions,
the correctness of the above analyses are validated. 相似文献
114.
Hot carriers injection (HCI) tests for ultra-short channel n-MOSFET
devices were studied. The experimental data of short channel devices
(75--90\,nm), which does not fit formal degradation power law well,
will bring severe error in lifetime prediction. This phenomenon
usually happens under high drain voltage ($V_{\rm d}$) stress
condition. A new model was presented to fit the degradation curve
better. It was observed that the peak of the substrate current under
low drain voltage stress cannot be found in ultra-short channel
device. Devices with different channel lengths were studied under
different $V_{\rm d}$ stresses in order to understand the relations
between peak of substrate current ($I_{\rm sub}$) and channel
length/stress voltage. 相似文献
115.
In current critical area models, it is generally assumed the defect outlines are
circular and the conductors to be rectangle or the merger of rectangles. However,
real defects and conductors associated with optimal layout design exhibit a great
variety of shapes. Based on mathematical morphology, a new critical area model is
presented, which can be used to estimate the critical area of short circuit, open
circuit and pinhole. Based on the new model, the efficient validity check algorithms
are explored to extract critical areas of short circuit, open circuit and pinhole
from layouts. The results of experiment on an approximate layout of ${4\times 4}$
shifts register show that the new model predicts the critical areas accurately.
These results suggest that the proposed model and algorithm could provide new
approaches for yield prediction. 相似文献
116.
The theoretic calculation and analysis of the temperature dependence of Hall electron density of a sample AlGaN/GaN heterostructure has been carried out in the temperature range from 77 to 300K. The densities of the two-dimensional electron gas and the bulk electrons are solved by self-consistent calculation of one-dimensional Schr?dinger and Poisson equations at different temperatures, which allow for the variation of energy gap and structure strain, and are used for evaluation of the temperature dependence of Hall electron density. The calculated Hall electron density agrees with the measured one quite well with the appropriate bulk mobility data. Analysis revealed that for the temperature range considered, even in the heterostructures with a small bulk conductance the factors that determine the Hall mobility and electron density could be of different sources, and not just the two-dimensional electron gas as generally supposed. 相似文献
117.
118.
HOT-CARRIER GENERATION MECHANISM AND HOT-CARRIER EFFECT IMMUNITY IN DEEP-SUB-MICRON GROOVED-GATE PMOSFETS 下载免费PDF全文
Based on the hydrodynamic energy transport model, immunity from the hot-carrier effect in deep-sub-micron grooved-gate p-channel metal-oxide-semiconductor field-effect transistors (PMOSFETs) is analysed. The results show that hot carriers generated in grooved-gate PMOSFETs are much smaller than those in planar ones, especially for the case of channel lengths lying in the deep-sub-micron and super deep-sub-micron regions. Then, the hot-carrier generation mechanism and the reason why grooved-gate MOS devices can suppress the hot-carrier effect are studied from the viewpoint of physical mechanisms occurring in devices. It is found that the highest hot-carrier generating rate is at a medium gate bias voltage in three stress areas, similar to conventional planar devices. In deep-sub-micron grooved-gate PMOSFETs, the hot-carrier injection gate current is still composed mainly of the hot-electron injection current, and the hole injection current becomes dominant only at an extremely high gate voltage. In order to investigate other influences of the hot-carrier effect on the device characteristics, the degradation of the device performance is studied for both grooved-gate and planar devices at different interface states. The results show that the drift of the device electrical performance induced by the interface states in grooved-gate PMOSFETs is far larger than that in planar devices. 相似文献
119.
The effects of channel length and width on the degradation of negative bias temperature instability (NBTI) are studied. With the channel length decreasing, the NBTI degradation increases. As tile channel edges have more damage and latent damage for the process reasons, the device can be divided into three parts: the gate and source overlap region, the middle channel region, and the gate and drain overlap region. When the NBTI stress is applied, the non-uniform distribution of the generated defects in the three parts will be generated due to the inhomogeneous degradation. With tile decreasing channel length, tile channel edge regions will take up a larger ratio to the middle channel region and the degradation of NBTI is enhanced. The channel width also plays an important role in the degradation of NBTI. There is an inflection point during the decreasing channel width. There are two particular factors: the lower vertical electric field effect for the thicker gate oxide thickness of the sha/low trench isolation (STI) edge and the STI mechanical stress effecting on the NBTI degradation. The former reduces and the latter intensifies the degradation. Under the mutual compromise of the both factors, when the effect of the STI mechanical stress starts to prevail over the lower vertical electric field effect with the channel width decreasing, the inflection point comes into being. 相似文献
120.
Improved mobility of AIGaN channel heterojunction material using an AIGaN/GaN composite buffer layer 下载免费PDF全文
The quality of an A1GaN channel heterojunction on a sapphire substrate is massively improved by using an A1- GaN/GaN composite buffer layer. We demonstrate an A10.4Gao.6N/AI0.18Ga0.82N heterojunction with a state-of-the-art mobility of 815 cm2/(V.s) and a sheet resistance of 890Ω/口 under room temperature. The crystalline quality and the electrical properties of the A1GaN heterojunction material are analyzed by atomic force microscopy, high-resolution X-ray diffraction, and van der Pauw Hall and capacitance-voltage (C-V) measurements. The results indicate that the improved electrical properties should derive from the reduced surface roughness and low dislocation density. 相似文献