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A comparative combined stress-induced reliability issues between Auger hot carrier and ionizing radiation in double polysilicon bipolar transistor is investigated. The observed differences in the low-frequency noise spectra of devices with different stressing conditions could be interpreted as the differences in the defects-related noise contributions. Low-frequency noise and electrical performance degradation results show that Auger hot carriers greatly induce the atomic hydrogen depassivating the dangling bonds in grain boundaries of emitter polysilicon. However, ionizing radiation damage occurs both at SiO2/Si interfaces and in the oxide layer. 1/f noise characteristics indicate that these two damages have different time dependences.

Acoustic resolution photoacoustic microscopy (AR-PAM) is a promising medical imaging modality that can be employed for deep bio-tissue imaging. However, its relatively low imaging resolution has greatly hindered its wide applications. Previous model-based or learning-based PAM enhancement algorithms either require design of complex handcrafted prior to achieve good performance or lack the interpretability and flexibility that can adapt to different degradation models. However, the degradation model of AR-PAM imaging is subject to both imaging depth and center frequency of ultrasound transducer, which varies in different imaging conditions and cannot be handled by a single neural network model. To address this limitation, an algorithm integrating both learning-based and model-based method is proposed here so that a single framework can deal with various distortion functions adaptively. The vasculature image statistics is implicitly learned by a deep convolutional neural network, which served as plug and play (PnP) prior. The trained network can be directly plugged into the model-based optimization framework for iterative AR-PAM image enhancement, which fitted for different degradation mechanisms. Based on physical model, the point spread function (PSF) kernels for various AR-PAM imaging situations are derived and used for the enhancement of simulation and in vivo AR-PAM images, which collectively proved the effectiveness of proposed method. Quantitatively, the PSNR and SSIM values have all achieve best performance with the proposed algorithm in all three simulation scenarios; The SNR and CNR values have also significantly raised from 6.34 and 5.79 to 35.37 and 29.66 respectively in an in vivo testing result with the proposed algorithm. Ministry of Education (MOE) Published version This research is supported by the Ministry of Education, Singapore, under its MOE ARF Tier 2 (Award no. MOE2019-T2-2-179).

Development work was conducted on N+PN+PN+ Poly silicon light-emitting devices which are compatible with silicon-based integrated circuit technology. We discuss the emission characteristics of visible light by a monolithically integrated Poly-Si diode under reverse bias. With the structure of modified PN junctions, the carriers injection occurs through silicon slabs of only a few nanometer thick. The dominant role of non-radiative recombination at the N+ and P+ contacts is diminished by confining the injected carriers around the PN junction’s interface in which avalanche takes place. The current-dependent optical radiation presents a broad spectrum in the 400- to 900-nm range. Although the emission efficiency is low due to silicon’s indirect bandgap, it is advantageous to utilize these devices in all-silicon optoelectronic integrated circuits (OIC’s).

Phenolic compounds can act as protective agents against free radical oxidation. It is desirable to develop simple and efficient analytical techniques to measure the phenolic content and their antioxidant capacity. Using Enteromorpha prolifera (EP) as the carbon source, novel fluorescent carbon dots (EP-CDs) were synthesized through a facile microwave-assisted hydrothermal method. EP-CDs exhibit high mono-dispersity in aqueous solution, low cytotoxicity, and dual fluorescence emission in the visible and near-infrared range. The fluorescence of EP-CDs is inert to phenolic compounds and hydroxyl free radicals, but could be rapidly and efficiently quenched by the quinoid oxidation products. By monitoring the fluorescence quenching of EP-CDs, it is demonstrated that the radical scavenging processes of different natural phenolic compounds could be sensitively detected. By employing this eco-friendly and economic analytical method, phenols with different structure or concentration could be rapidly detected and determined. EP-CDs also have potential for additional applications, such as hydrogen peroxide and iron analysis.

Aiming at the severe effect of poly-silicon deposition process on the performance of polysilicon swtich, experiments were made on optimization of poly-silicon deposition and releasing the stress of polysilicon beams to obtain optimal process conditions. By using the optimizing process, the fabrication process for polysilicon mechanical switch is designed, and a poly-silicon micromachined RF MEMS(radio frequency microelectronic machined system) switch has been fabricated. The switch is tested, the results are as follows: the off-state capacitance and on-state capacitance are 0.1 p F and 2.5p F , respectively, and the pull down voltage is 45V. Those optimizing key process technology for fabrication polysilicon mechanical switches is useful, and will be a base for developing RF switch systems with IC.

The concentrations of polycyclic aromatic hydrocarbons (PAHs) in the leachate from the gangue and 20 groundwater samples, which were collected from the 12th Coal Mine around gangue piles in Henan Province, China, were determined by SPE-GC-MS. The characteristics of PAHs pollutants in groundwater were investigated, and compared with the concentrations of PAHs in the leachate from different weathered gangues to discuss the pollution effects of PAHs from coal gangue on groundwater. The results showed that total concentrations of the 16 EPA preferentially controlled PAHs ranged from 146.9 ng/L to 1220.6 ng/L.The components of PAHs such as chrysene, benzo[a]anthracene, benzo[b + k]fluoranthene, indeno[1,2,3-c,d]–pyrene, and dibenz[a,h]anthracene were fairly high. The 2–4 rings PAHs such as naphthalene, phenanthrene, fluorene and chrysene were dominant in groundwater, which was similar to those of the leachate from the different weathered gangues. Therefore, it should be paid much more attention on the transport of lower ring numbered PAHs leached by rains from the coal mines after landfilling and dumping. Based on the spatial distribution of PAHs and the high concentrations of PAHs with 2–4 rings in groundwater and leaching samples, there might be other pollution sources of PAHs except for penetration from coal gangue into groundwater in the Pingdingshan coal mine area.

In this paper, the threshold voltage model using a quasi -2D approximation for deep submicron double-gate fully-depleted SOI PMOS devices was described by solving basic semiconductor physical equations. Taking into consideration the distribution of minority carriers in the silicon film, the analytical threshold voltage model to make an accurate prediction of short-channel effect has been obtained, and also a further threshold voltage model including DIBL effect and interface charge effect was obtained. The analytical voltage model applies also to SOI NMOS devices. All of the above models have been verified by the results of 2D device simulator MEDICI.

In this paper, the threshold voltage model using a quasi-2D approximation for deep submicrometer double-gate fully-depleted SOI PMOS devices was described by solving basic semiconductor physical equations. Taking into consideration the distribution of minority carriers in the silicon film, the analytical threshold voltage model to make an accurate prediction of short- channel effect has been obtained, and also a further threshold voltage model including DIBL effect and interface charge effect was obtained. The analytical voltage model applies also to SOI NMOS devices. All of the above models have been verified by the results of 2D device simulator MEDICI.

An improved breakdown voltage (BV) SOI power MOSFET with a reduced cell pitch is proposed and fabricated. Its breakdown characteristics are investigated numerically and experimentally. The MOSFET features dual trenches (DTMOS), an oxide trench between the source and drain regions, and a trench gate extended to the buried oxide (BOX). The proposed device has three merits. First, the oxide trench increases the electric field strength in the x-direction due to the lower permittivity of oxide (eox) than that of Si (eSi). Furthermore, the trench gate, the oxide trench, and the BOX cause multi-directional depletion, improving the electric field distribution and enhancing the RESURF (reduced surface field) effect. Both increase the BV. Second, the oxide trench folds the drift region along the y-direction and thus reduces the cell pitch. Third, the trench gate not only reduces the on-resistance, but also acts as a field plate to improve the BV. Additionally, the trench gate achieves the isolation between high-voltage devices and the low voltage CMOS devices in a high-voltage integrated circuit (HVIC), effectively saving the chip area and simplifying the isolation process. An 180 V prototype DTMOS with its applied drive IC is fabricated to verify the mechanism.

A low on-resistance (Ron,sp) integrable silicon-on-insulator (SOI) n-channel lateral double-diffused metal-oxide-semiconductor (LDMOS) is proposed and its mechanism is investigated by simulation. The LDMOS has two features: the integration of a planar gate and an extended trench gate (double gates (DGs)); and a buried P-layer in the N-drift region, which forms a triple reduced surface field (RESURF) (TR) structure. The triple RESURF not only modulates the electric field distribution, but also increases N-drift doping, resulting in a reduced specific on-resistance (Ron,sp) and an improved breakdown voltage (BV) in the off-state. The DGs form dual conduction channels and, moreover, the extended trench gate widens the vertical conduction area, both of which further reduce the Ron,sp. The BV and Ron,sp are 328 V and 8.8 m??cm2, respectively, for a DG TR metal-oxide-semiconductor field-effect transistor (MOSFET) by simulation. Compared with a conventional SOI LDMOS, a DG TR MOSFET with the same dimensional device parameters as those of the DG TR MOSFET reduces Ron,Sp by 59% and increases BV by 6%. The extended trench gate synchronously acts as an isolation trench between the high-voltage device and low-voltage circuitry in a high-voltage integrated circuit, thereby saving the chip area and simplifying the fabrication processes.

A novel structure of a VDMOS in reducing on-resistance is proposed. With this structure, the specific on-resistance value of the VDMOS is reduced by 22% of that of the traditional VDMOS structure as the breakdown voltage maintained the same value in theory, and there is only one additional mask in processing the new structure VDMOS, which is easily fabricated. With the TCAD tool, one 200 V N-channel VDMOS with the new structure is analyzed, and simulated results show that a specific on-resistance value will reduce by 23%, and the value by 33% will be realized when the device is fabricated in three epitaxies and four buried layers. The novel structure can be widely used in the strip-gate VDMOS area.

A new quite simple analytical model based on the charge allocating approach has been proposed to describe the breakdown property of the RESURF (reduced surface field) structure. It agrees well with the results of numerical simulation on predicting the breakdown voltage. Compared with the latest published analytical model, this model has a better accuracy according to the numerical simulation with simpler form. The optimal doping concentration (per unit area) of the epi-layer of the RESURF structures with different structure parameters has been calculated based on this model and the results show no significant discrepancy to the data gained by others. Additionally the physical mechanism of how the surface field is reduced is clearly illustrated by this model.