AVS 46th International Symposium
    Electronic Materials and Processing Division Monday Sessions
       Session EM-MoM

Invited Paper EM-MoM1
GaN Growth Chemistry, System Design and Materials Properties

Monday, October 25, 1999, 8:20 am, Room 608

Session: Nitride Epitaxy
Presenter: T.F. Kuech, University of Wisconsin, Madison
Authors: T.F. Kuech, University of Wisconsin, Madison
J. Sun, University of Wisconsin, Madison
L. Zhang, University of Wisconsin, Madison
J.M. Redwing, Epitronics
Correspondent: Click to Email
The growth of device-quality GaN by metal-organic vapor phase epitaxy (MOVPE) is often difficult to achieve. The MOVPE growth of GaN is complicated by the extensive and pervasive complex gas phase chemistry within the growth system. This gas phase chemistry leads to the high sensitivity of the materials properties on the detailed fluid dynamics within the system. Through the combination of reactor modeling and gas phase kinetic studies, we have identified a stratified gas phase chemical structure within the reactor that leads to such process complexities. The high gas phase flow rates employed in GaN MOVPE results in a very thin high-temperature gas flow region above the growth front that leads to extremely high thermal gradients. Inside this thin high-temperature flow region, dominant chemical species above the growth surface changes in the gas phase above the growth front as a result of the high thermal gradient present and the high molecular weight species resulting from the oligimerization of the adduct. This chemically stratified region is closely related to the transport and reaction behavior present in GaN MOVPE processes and the modeling of this near-growth-front region serves as an engineering guideline for GaN MOVPE reactor design. We have combined these numerical results with detailed experimental measurements within the modeled system. The implications of these findings for the design of GaN systems and materials performance will be discussed. The extension of these models to the case of selective are growth of GaN will be discussed in terms of the local gas phase activities of the reactants and their influence on the facet formation.