Modelling of interconnects in 3DIC based on layered green functions

As traditional CMOS scaling pace gradually slows down, three-dimensional (3D) integration offers another dimension of in the ”More-than-Moore” era. In this dissertation, a number of investigations were conducted to better model interconnects in 3D integrated circuit (IC), to evaluate electrical behavior including delay, power consumption, signal integrity (SI), and power integrity (PI) for 3D ICs. Partial Element Equivalent Circuit (PEEC) method with layered Green’s function is studied here, since it consumes less computational resources and provides better physical insight to model the interconnects in 3DIC for high-speed digital circuits. The work is organized as a series of papers. The first paper reviewed the fundamental methods to derive layered Green’s function in spectral domain using discrete complex image method (DCIM) and analyzed the effects of each Green function terms to model silicon interconnects. The second paper proposed a unique method to extract poles near branch cut in complex kp plane, to accurately extract surface wave effects. The last paper proposed a new equivalent circuit model for coplanar waveguide (CPW) structure on 3DIC. The silicon effects on series inductance were also studied by employing the modified Green functions with semiconductor images at a complex distance from spectral-domain analysis. --Abstract, page iii

Modeling and analysis of high-speed sources and serial links for signal integrity

As the computer and electronics industry moves towards higher data rates, signal integrity and electromagnetic interference (EMI) problems always present challenges for designers for high-speed data communication systems. To characterize the entire link path between transmitters and receivers, accurate models for sources, passive link path (such as traces, vias, connectors, etc), and terminations should be built before simulations either in frequency or time domain. Due to the imperfection of model, data corrections are preferred before time-domain simulations to ensure stability. Moreover, data obtained from models should be compared with measurement results to judge the level of agreement for validations. This thesis presents a new approach to model via structures to help design signal link path while maintaining a low insertion loss and minimizing crosstalk, borrowing the concepts from the transmission line theories. For the models of sources, a dipole model is proposed to represent integrated circuit (IC) radiation emissions while a circuit model for I/O current source is proposed for IC conductive emissions. Passivity and causality are two important properties for passive networks. This thesis also presents detailed algorithm to check passivity and causality for networks with arbitrary port numbers. Data corrections in term of passivity and causality enforcement are applied based on matrix perturbation theory. Last but not least, Feature Selective Validation (FSV) technique is expanded in this thesis to quantify the comparisons of data sets and provide quantitative standard for data optimization --Abstract, page iii

Low threading dislocation density and antiphase boundary free GaAs epitaxially grown on on-axis Si (001) substrates

The interactions between 1D defect threading dislocations and 2D defect antiphase boundaries and antiphase boundary annihilation in III–V materials on Si heteroepitaxy growth are revealed

RenderMe-360: A Large Digital Asset Library and Benchmarks Towards High-fidelity Head Avatars

Synthesizing high-fidelity head avatars is a central problem for computer vision and graphics. While head avatar synthesis algorithms have advanced rapidly, the best ones still face great obstacles in real-world scenarios. One of the vital causes is inadequate datasets -- 1) current public datasets can only support researchers to explore high-fidelity head avatars in one or two task directions; 2) these datasets usually contain digital head assets with limited data volume, and narrow distribution over different attributes. In this paper, we present RenderMe-360, a comprehensive 4D human head dataset to drive advance in head avatar research. It contains massive data assets, with 243+ million complete head frames, and over 800k video sequences from 500 different identities captured by synchronized multi-view cameras at 30 FPS. It is a large-scale digital library for head avatars with three key attributes: 1) High Fidelity: all subjects are captured by 60 synchronized, high-resolution 2K cameras in 360 degrees. 2) High Diversity: The collected subjects vary from different ages, eras, ethnicities, and cultures, providing abundant materials with distinctive styles in appearance and geometry. Moreover, each subject is asked to perform various motions, such as expressions and head rotations, which further extend the richness of assets. 3) Rich Annotations: we provide annotations with different granularities: cameras' parameters, matting, scan, 2D/3D facial landmarks, FLAME fitting, and text description. Based on the dataset, we build a comprehensive benchmark for head avatar research, with 16 state-of-the-art methods performed on five main tasks: novel view synthesis, novel expression synthesis, hair rendering, hair editing, and talking head generation. Our experiments uncover the strengths and weaknesses of current methods. RenderMe-360 opens the door for future exploration in head avatars.Comment: Technical Report; Project Page: 36; Github Link: https://github.com/RenderMe-360/RenderMe-36

All-MBE grown InAs/GaAs quantum dot lasers with thin Ge buffer layer on Si substrates

A high-performance III–V quantum-dot (QD) laser monolithically grown on Si is one of the most promising candidates for commercially viable Si-based lasers. Great efforts have been made to overcome the challenges due to the heteroepitaxial growth, including threading dislocations and anti-phase boundaries, by growing a more than 2 µm thick III–V buffer layer. However, this relatively thick III–V buffer layer causes the formation of thermal cracks in III–V epi-layers, and hence a low yield of Si-based optoelectronic devices. In this paper, we demonstrate a usage of thin Ge buffer layer to replace the initial part of GaAs buffer layer on Si to reduce the overall thickness of the structure, while maintaining a low density of defects in III–V layers and hence the performance of the InAs/GaAs QD laser. A very high operating temperature of 130 °C has been demonstrated for an InAs/GaAs QD laser by this approach

Multi-wavelength 128 Gbit s−1 λ−1 PAM4 optical transmission enabled by a 100 GHz quantum dot mode-locked optical frequency comb

Semiconductor mode-locked lasers (MLLs) with extremely high repetition rates are promising optical frequency comb (OFC) sources for their usage as compact, high-efficiency, and low-cost light sources in high-speed dense wavelength-division multiplexing transmissions. The fully exploited conventional C- and L- bands require the research on O-band to fulfil the transmission capacity of the current photonic networks. In this work, we present a passive two-section InAs/InGaAs quantum-dot (QD) MLL-based OFC with a fundamental repetition rate of ∼100 GHz operating at O-band wavelength range. The specially designed device favours the generation of nearly Fourier-transform-limited pulses in the entire test range by only pumping the gain section while with the absorber unbiased. The typical integrated relative intensity noise of the whole spectrum and a single tone are −152 and −137 dB Hz−1 in the range of 100 MHz–10 GHz, respectively. Back-to-back data transmissions for seven selected tones have been realised by employing a 64 Gbaud four-level pulse amplitude modulation format. The demonstrated performance shows the feasibility of the InAs QD MLLs as a simple structure, easy operation, and low power consumption OFC sources for high-speed fibre-optic communications

3% diquafosol sodium eye drops in Chinese patients with dry eye: a phase IV study

IntroductionThe efficacy and safety of 3% diquafosol sodium eye drops in Chinese patients with dry eye in the real-world setting remains unclear.Methods3099 patients with dry eye symptoms were screened according to Asia Dry Eye Society latest recommendation. Among them, 3000 patients were enrolled for a phase IV study. We followed up with multiple clinical characteristics including corneal fluorescein staining, tear break up time, Schirmer’s tests, visual acuity, intraocular pressure, and others. The follow ups were performed at baseline, 2 weeks and 4 weeks after treatment.ResultsBased on the results of corneal fluorescein staining and tear break up time, all age and gender subgroups exhibited obvious alleviation of the symptoms among the patients with dry eye, and the data in elderly group showed the most significant alleviation. All the adverse drug reactions (ADRs, 6.17%) were recorded, among which 6% local ocular ADRs were included. Meanwhile, mild ADRs (91.8%) accounted for the most. Most of the ADRs (89.75%) got a quick and full recovery, with an average time at 15.6 days. 1.37% of patients dropped out of the study due to ADRs.DiscussionThe use of 3% diquafosol sodium eye drop is effective and safe in the treatment of dry eye, with a low incidence of ADRs showing mild symptoms. This trial was registered at Chinese Clinical Trial Registry ID: ChiCTR1900021999 (Registration Date: 19/03/2019)

An Efficient Method to Extract Surface-Wave Poles of Green\u27s Functions near Branch Cut in Lossy Layered Media

Calculating the Green\u27s functions in lossy layered media using the discrete complex image method (DCIM) is challenging, due to the difficulties in extracting the surface-wave poles that are very close to a branch cut. An efficient algorithm based on the contour method is proposed in this communication to locate these poles and calculate the residues. The proposed method is robust for both the lossless and lossy media. With the proposed approach, it is shown in numerical examples that some poles, very close to a branch cut, are successfully extracted in lossy media. The accurate calculation of the Green\u27s functions in lossy layered media enables the accurate and efficient modeling of complex structures in lossy semiconductor substrates and new 3D IC structures including through-silicon vias (TSVs)

Green\u27s Functions in Lossy Multi-Layer Dielectrics for 3D IC/Packaging Applications

Green\u27s function in lossy multi-layer dielectrics is presented using DCIM method for 3D IC/packaging in this paper. Loss effects in layered medium are analysed through the components extracted from DCIM. The proposed layered Green\u27s function can be used for 3D IC and packaging applications

De-Embedding Techniques for Transmission Lines: An Application to Measurements of On-Chip Coplanar Traces

In this paper, the de-embedding study presented in [1] is extended from the simulation environment to the measurement environment; the three presented de-embedding methods are applied to measurements of on-chip coplanar traces for two different test ICs. Additionally, the Hybrid technique presented in [1] is reformulated so that only two measurement standards are required, as opposed to three. The results of de-embedding the measurement data are discussed, as well as challenges with making the measurements