The following 3 short courses will be given before the workshop on Sunday June 7th 2009. The fee will be 50€ for each:
|8:30 - 10.00||Fundamentals of crystal growth and epitaxy|
Maarten Leys, IMEC Leuven, Belgium
In this course the fundamental aspects of crystal growth and epitaxy will be discussed. We will first focus on thermodynamic aspects of equilibrium, etching and growth. Computer simulations (movies) will be shown to demonstrate the concept of 2 dimensional nucleation and the critical cluster size. Also, the effects of dislocations and impurities are made clear. Next, we will consider substrates and surface structures/reconstructions. Getting closer to practice the VPE processes of Si and GaAs will be discussed. Finally we will consider MBE as growth technique for both GaAs as well as GaN.
|10:15 - 11:45||In-situ optical techniques for MOVPE|
Nigel Mason, United Kingdom
Over the last 15 years, the understanding of the chemical and physical processes occurring within the MOVPE reactor have been transformed by the use of an increasing number of optical tools to measure such parameters as the crystal surface reconstruction, gas phase chemical composition, growth rate, wafer bow and wafer temperature uniformity. The measurement of the above parameters has been achieved using a variety of white-light based techniques including simple reflectance, ellipsometry, reflectance-difference and reflectance-anisotropy. Monochromatic techniques used include reflectance [both normal and at Brewster's angle] as well as laser light scattering. Both types of approach can give very precise information about both the real and imaginary components of the materials refractive index and hence growth rate and crystal film quality. Wafer temperatures can be measured by a variety of techniques including band-edge determination and pyrometry.
|12:00 - 13:30||Production process design for electronic devices with focus on epitaxy: GaN-based Heterostructure Field-Effect Transistors|
Frank Brunner, FBH Berlin, Germany
|FBH promotes rapid transfer of technology to industrial partners and spin-offs which makes implementation of small-scale pilot production processes mandatory. This course aims at highlighting issues of epitaxial process design at the intersection between applied device research and industrial production. Establishing an epi production process covers different aspects from securing the supply chain of consumables like precursors up to utilization of non-destructive analytic tools. Using the example of GaN-based heterostructure field effect transistors (HFETs) we will highlight these epitaxy-specific issues including substrate qualification, in-situ monitoring and layer characterization. Standard production design tools like statistical process control are used to demonstrate the impact on MOVPE machine uptime and yield. Examples of reproducibility (run-to-run and wafer-to-wafer) and wafer uniformity of critical layer parameters, i.e. AlGaN barrier thickness and composition, will be presented.|