Victor Chaly

Bio: Victor Chaly is an academic researcher. The author has contributed to research in topics: Transistor & Molecular beam epitaxy. The author has an hindex of 1, co-authored 2 publications receiving 1 citations.

AlN/AlGaN/GaN/AlGaN multilayer heterostructures with quantum well channel on heat conducting substrates for power microwave transistors

Abstract: Molecular beam epitaxy using ammonia as a nitrogen source is applied to obtain III-nitride multilayer heterostructures having high structural quality and low dislocation density. To provide strong carrier confinement in two-dimensional electron gas for collapse-free transistor operation, GaN quantum well as thin as 5 nm was formed between AlGaN barrier layers of various Al content, keeping high sheet conductivity in 280-350 Ohm/square range. Due to rather thick AlN “template” grown at extremely high (up to 1200 °C) substrate temperatures directly in the same growth run prior to the growth of heterostructure, technology developed on sapphire is easily transferred to alternative substrates, for example AlN/SiC or Si. In contrast to sapphire, where noticeable drop of transistor saturation current at drain voltages higher than 5-10 V is usually observed, heat conducting substrates allow to avoid this negative thermal effect and no drop is observed at drain voltages up to 20 V and even higher. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Industrial Technologies For III-Nitride-Based Electronics.

Abstract: The industrial level technologies including molecular beam epitaxy and submicron planar processing are developed to realize novel electron devices based on III-nitride multilayer heterostructures. Wide conditions range available on growth equipment used as well as flexible heterostructure designs allows controlling of device oriented material properties. For microwave applications, thick AlN “templates” grown at extremely high (up to 1100°C) substrate temperature in conjunction with multilayer transition region design both provide low dislocation density in the order of 10 8 cm -2 . The strong carrier confinement in two-dimensional electron gas for collapse-free transistor operation is provided by placing GaN channel between AlGaN barriers of various Al content, keeping high sheet conductivity of 260-320 Ohm/square. Based on these heterostructures a number of power amplifiers for L-, S-, C- and X-band are realized. For various types of bulk acoustic resonators, stress-controlling technology of AlN/GaN layers having high depth uniformity on Si substrates is also developed.

Semiconductor light emitting device and semiconductor wafer

Abstract: According to one embodiment, a semiconductor light emitting device includes a first semiconductor layer of a first conductivity type, a second semiconductor layer of a second conductivity type, and a light emitting layer provided between the first semiconductor layer and the second semiconductor layer and configured to emit a light having a peak wavelength of 440 nanometers or more. Tensile strain is applied to the first semiconductor layer. An edge dislocation density of the first semiconductor layer is 5×109/cm2 or less. A lattice mismatch factor between the first semiconductor layer and the light emitting layer is 0.11 percent or less.