P. J. W. Severin

Bio: P. J. W. Severin is an academic researcher. The author has contributed to research in topics: Epitaxy & Silane. The author has an hindex of 1, co-authored 2 publications receiving 250 citations.

Role of Kinetic Factors in Chemical Vapor Deposition Synthesis of Uniform Large Area Graphene Using Copper Catalyst

Abstract: In this article, the role of kinetics, in particular, the pressure of the reaction chamber in the chemical vapor deposition (CVD) synthesis of graphene using low carbon solid solubility catalysts (Cu), on both the large area thickness uniformity and the defect density are presented. Although the thermodynamics of the synthesis system remains the same, based on whether the process is performed at atmospheric pressure (AP), low pressure (LP) (0.1−1 Torr) or under ultrahigh vacuum (UHV) conditions, the kinetics of the growth phenomenon are different, leading to a variation in the uniformity of the resulting graphene growth over large areas (wafer scale). The kinetic models for APCVD and LPCVD are discussed, thereby providing insight for understanding the differences between APCVD vs LPCVD/UHVCVD graphene syntheses. Interestingly, graphene syntheses using a Cu catalyst in APCVD processes at higher methane concentrations revealed that the growth is not self-limiting, which is in contrast to previous observatio...

Step-controlled epitaxial growth of SiC: High quality homoepitaxy

Abstract: Chemical vapor deposition (CVD) of silicon carbide (SiC) onto SiC{0001} substrates and its device applications are reviewed. Polytype-controlled epitaxial growth of SiC, which utilizes step-flow growth on off-oriented SiC{0001} substrates (step-controlled epitaxy), is proposed, and the detailed growth mechanism is discussed. In step-controlled epitaxy, SiC growth is controlled by the diffusion of reactants in a stagnant layer. Critical growth conditions where the growth mode changes from step-flow to two-dimensional nucleation are predicted as a function of growth conditions using a model describing SiC growth on vicinal {0001} substrates. Step bunching on the surfaces of SiC epilayers, nucleation, and step-dynamics are also investigated. The high quality of SiC epilayers was elucidated through low-temperature photoluminescence, Hall effect, and deep level measurements. Excellent doping controllability over a wide range was obtained by in situ doping of a nitrogen donor and aluminum/boron acceptors. Recent progress in SiC device fabrication using step-controlled epitaxial layers is presented. The intrinsic potential of SiC is demonstrated in the excellent performance of high-power, high-frequency, and high-temperature devices, which will develop novel electronics.

The fundamentals of chemical vapour deposition

Abstract: Fundamentals of the chemical vapour deposition process are described and examples given of its application. The most important aspects of the process are reviewed; these include deposit structure (with its relation to process parameters), process control through application of the principles of thermodynamics and reaction kinetics (with emphasis on deposit thickness uniformity, deposit composition control and deposit-substrate adherence) and basic design features of the equipment used.