Accurate large-signal equivalent circuit of surface channel diamond FETs based on the Chalmers model

The paper presents a large-signal nonlinear circuit-oriented model for polycrystalline and single-crystal H-terminated diamond MESFETs implemented within the Agilent ADS design suite. The DC characteristics of such devices suggest that the channel free charge control law may be modeled using the same strategy adopted for III-V HEMTs. For this reason, the well-known nonlinear Chalmers (Angelov) circuit model was chosen as the starting point for the development of the present non-linear diamond MESFET model. Model fitting was performed against DC and multibias small signal measurements, with good agreement. Model validations versus large-signal (power) measurements point out the accuracy of the proposed approach to simulate the behavior of H-terminated diamond MESFETs under large-signal operatio

Chemical vapour deposition synthetic diamond: materials, technology and applications

Substantial developments have been achieved in the synthesis of chemical vapour deposition (CVD) diamond in recent years, providing engineers and designers with access to a large range of new diamond materials. CVD diamond has a number of outstanding material properties that can enable exceptional performance in applications as diverse as medical diagnostics, water treatment, radiation detection, high power electronics, consumer audio, magnetometry and novel lasers. Often the material is synthesized in planar form, however non-planar geometries are also possible and enable a number of key applications. This article reviews the material properties and characteristics of single crystal and polycrystalline CVD diamond, and how these can be utilized, focusing particularly on optics, electronics and electrochemistry. It also summarizes how CVD diamond can be tailored for specific applications, based on the ability to synthesize a consistent and engineered high performance product.Comment: 51 pages, 16 figure

Планы практических занятий по курсу "Основы управления интеллектуальной собственностью"

Diamond is a wide bandgap semiconductor with extremely attractive properties but also many technological difficulties. Doping is restricted to deep impurities and substrate size is very limited. Nevertheless in proof of concept experiments, the potential for high power, high temperature and high frequency applications can already well be estimated. In addition, first passive MEMS elements for advanced circuit applications have also been demonstrated, however still on nano-crystalline material, which is available with large surface area. Thus it is already possible to discuss an integrated systems approach when single crystal substrates in wafer size become available

Ultra-nano-crystalline/single crystal diamond heterostructure diode

A new type of highly rectifying diamond heterostructure diode is demonstrated. The p-type doped part of the diode consists of a single crystal diamond, the n-type part of a nitrogen doped ultra-nano-crystalline diamond (UNCD) layer. IV-measurements show 8 orders of magnitude of rectification (±10 V) at room temperature. The barrier behavior is rather complex and can be described by two junctions acting in parallel, reflecting the UNCD properties. This new material system displays an extraordinary thermal stability and has been tested successfully up to 1050 °C in vacuum. Thus, this novel diamond heterostructure diode belongs to the few ultrahigh temperature stable electronic devices

A new diamond based heterostructure diode

A diamond based heterostructure diode containing a p-type doped diamond active layer and an n-type doped ultra-nano-crystalline top layer has been investigated. Analysis suggests that the configuration is that of a merged diode, containing two areas of different interfacial barrier potentials in parallel related to the ultra-nano-crystalline grains and the grain boundaries, respectively. Thus this heterostructure may be ideally suited to combine low forward losses with high blocking voltages in diamond high power rectifiers

Electronic properties and applications of ultrananocrystalline diamond

Ultrananocrystalline diamond (UNCD) is a 3–5 nm grain size material with many of the properties of diamond. Whilst intrinsic UNCD films display a mild p-type characteristic with high resistivity, the addition of nitrogen to the gas phase during deposition renders the material n-type with low resistivity and activation energy. Hall effect measurements as a function of temperature show that this conductivity mechanism is semi - metallic, with the carrier concentration decreasing very gradually with decreasing temperature. Increasing the nitrogen content in the gas phase during deposition results in higher carrier concentrations in the deposited films and lower activation energies. The carrier mobilities of the films are limited by the grain size of the films. A prototype heterostructure diode is demonstrated, combining single crystal and ultrananocrystalline diamond