Fei Cao

Bio: Fei Cao is an academic researcher from Harbin Engineering University. The author has contributed to research in topics: Diffusion barrier & Materials science. The author has an hindex of 8, co-authored 35 publications receiving 185 citations.

Research of Single-Event Burnout in Power Planar VDMOSFETs by Localized Carrier Lifetime Control

Abstract: This paper presents 2-D numerical simulation results of single-event burnout (SEB) in power planar vertical double-diffused MOSFET (VDMOSFET) with localized carrier lifetime control. A low carrier lifetime control region (LCLCR) is introduced to accelerate the recombination rate of the generated holes caused by an ion's impact. The optimal localized range with LCLCR in epitaxial layer has been investigated. The SEB inhibition mechanism with LCLCR is analyzed and discussed. A VDMOSFET with localized LCLCR can operate like a normal VDMOSFET and can have improved SEB performance effectively. In addition, the leakage current density in breakdown characteristics of VDMOSFET is studied based on the variation of carrier lifetime.

Investigation of Zr–Si–N∕Zr bilayered film as diffusion barrier for Cu ultralarge scale integration metallization

Abstract: The effectiveness of ZrSiN∕Zr bilayered films to serve as diffusion barriers in Cu∕Si contacts has been investigated. Annealing studies for Cu∕ZrSiN∕Zr∕Si contact systems were carried out in N2∕H2(10%) ambient. X-ray diffraction data suggest that Cu film has preferential (111) crystal orientation and Cu silicide cannot be observed up to 700°C. Scanning electron microscopy micrographs show that the Cu film was integrated and free from agglomeration after annealing at 700°C. Auger electron spectroscopy depth profiles of the Cu∕ZrSiN(10nm)∕Zr(20nm)∕Si samples have no noticeable change except Zr silicide grows with annealing temperature up to 700°C. The results indicate excellent barrier property for ZrSiN(10nm)∕Zr(20nm) bilayer structure for Cu metallization.

A Novel Trench-Gated Power MOSFET With Reduced Gate Charge

Abstract: In this letter, we propose a novel trench power MOSFET structure with a p-n junction in trench to reduce the gate charge We utilize the 2-D device simulator, ATLAS, to investigate the characteristics of the proposed structure and compare with the conventional structure As a result, the proposed structure exhibits 495% enhancement in gate-charge $Q_{\mathrm {\mathbf {g}}}$ as compared with the conventional structure, without degrading the other electrical characteristics

High-entropy ceramics: Review of principles, production and applications

Abstract: High-entropy ceramics with five or more cations have recently attracted significant attention due to their superior properties for various structural and functional applications. Although the multi-component ceramics have been of interest for several decades, the concept of high-entropy ceramics was defined in 2004 by producing the first high-entropy nitride films. Following the introduction of the entropy stabilization concept, significant efforts were started to increase the entropy, minimize the Gibbs free energy and achieve stable single-phase high-entropy ceramics. High-entropy oxides, nitrides, carbides, borides and hydrides are currently the most popular high-entropy ceramics due to their potential for various applications, while the study of other ceramics, such as silicides, sulfides, fluorides, phosphides, phosphates, oxynitrides, carbonitrides and borocarbonitrides, is also growing fast. In this paper, the progress regarding high-entropy ceramics is reviewed from both experimental and theoretical points of view. Different aspects including the history, principles, compositions, crystal structure, theoretical/empirical design (via density functional theory, molecular dynamics simulation, machine learning, CALPHAD and descriptors), production methods and properties are thoroughly reviewed. The paper specifically attempts to answer how these materials with remarkable structures and properties can be used in future applications.

Structural and Thermodynamic Factors of Suppressed Interdiffusion Kinetics in Multi-component High-entropy Materials

Abstract: We report multi-component high-entropy materials as extraordinarily robust diffusion barriers and clarify the highly suppressed interdiffusion kinetics in the multi-component materials from structural and thermodynamic perspectives. The failures of six alloy barriers with different numbers of elements, from unitary Ti to senary TiTaCrZrAlRu, against the interdiffusion of Cu and Si were characterized, and experimental results indicated that, with more elements incorporated, the failure temperature of the barriers increased from 550 to 900°C. The activation energy of Cu diffusion through the alloy barriers was determined to increase from 110 to 163 kJ/mole. Mechanistic analyses suggest that, structurally, severe lattice distortion strains and a high packing density caused by different atom sizes, and, thermodynamically, a strengthened cohesion provide a total increase of 55 kJ/mole in the activation energy of substitutional Cu diffusion, and are believed to be the dominant factors of suppressed interdiffusion kinetics through the multi-component barrier materials.