Die metallorganische Gasphasenepitaxie (MOVPE) ist ein wichtiger Verarbeitungsschritt in der Halbleiterprozesstechnik zur Herstellung von III-V-Verbindungshalbleitern, auf deren Grundlage moderne elektronische und optoelektronische Bauelemente hergestellt werden. Daher besteht ein großer Bedarf hinsichtlich der Optimierung bestehender Verfahren bzw. der Untersuchung des Potenzials von neuen Prozessen, beispielsweise durch den Einsatz von alternativen Prekursoren. Ziel ist es dabei, eine Verbesserung der Qualität der abgeschiedenen kristallinen Schichten zu erhalten. Hierbei spielt in mehrfacher Hinsicht die numerische Simulation eine zunehmende Rolle. Zum einen lassen sich auf diesem Wege wichtige Prozessparameter vorab berechnen, vorausgesetzt die dem Prozess zugrunde liegenden physikalischen und chemischen Vorgänge lassen sich hinreichend genau quantifizieren. Zum anderen bietet die numerische Simulation Ansätze, die zu einem tieferen Verständnis dieser physikalischen und chemischen Vorgänge führen können.

The prediction of MOVPE processes requires the modeling of numerous coupled transport phenomena for momentum, mass and heat including temperature dependent physical properties and chemical reactions. In the present paper, the numerical simulation is used as a tool to identify and distinguish systematically the chemical parameters in the AlGaN growth process in order to obtain a reliable and efficient prediction of the process.

The prediction of MOVPE processes requires the modelling of numerous coupled transport phenomena for momentum, mass and heat including temperature dependent physical properties and chemical reactions. In the present paper, the numerical simulation is used as a tool to identify and distinguish systematically the important parameters in the AlGaN growth process. A reliable prediction of the essential parameters in MOVPE production devices, in particular of the deposition rates, requires accurate model parameters and realistic approximations of operating conditions entering as boundary conditions in the simulation process. However, the lack of microscopic data for the transport phenomena of the participating gases and the uncertainties in quantifying the reaction kinetics are major obstacles towards the use of the numerical simulation as a reliable design tool. To overcome this difficulty, a systematic study of the AlGaN growth process is presented. The sensitivity of different approaches for the computation of gas-mixture transport coefficients with respect to the heat and mass transport and thus, the deposition rates, is studied. For the chemistry mechanisms under consideration, the rates of reactions for the adduct and oligomer formation and decomposition are studied. These data were predicted in accordance with the corresponding data available in the literature. According to the results obtained, the adduct and oligomer formation is much more important in the AlN growth process than in the GaN growth process. The presented parametrical variations allow the assessment of the models used. Besides that, they allow to distinguish the main reaction pathways and thus to improve the understanding of the chemical kinetics. In order to confirm that, experimental results are presented for validation wherever possible.

A novel titanium precursor was used for TiO2 deposition in low pressure chemical vapor deposition reactor. The deposition kinetic was experimentally studied and used in a detailed three-dimensional reactor model. The model was validated by comparison with the experimentally observed growth rate distribution as a function of the growth temperatures.