In‐situ and real‐time monitoring of MOCVD growth of III‐nitrides by simultaneous multi‐wavelength‐ellipsometry and X‐ray‐diffraction

Abstract

Metal Organic Chemical Vapor Deposition (MOCVD) is nowadays the most frequently used industrial method for growing III‐nitrides. The possible spectrum of in‐situ diagnostic tools is quite narrow because the MOCVD growth process excludes all techniques based on ultra high vacuum conditions. Therefore, only optical methods like spectroscopic ellipsometry and X‐ray diffraction give the possibility to observe and analyse the growing surface in‐situ. We attached simultaneously a multi wavelength spectroscopic ellipsometer and a X‐ray diffraction system to our reactor and could determine parameters like growth rate and layer composition from both techniques. On the one hand the optical measurement gives surface sensitive information about the sample. On the other hand the measurement of the diffraction peak of hexagonal GaN and related alloys during growth gives additional information about the entire structure and the crystal quality. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

ParamagneticGaN:Feand ferromagnetic(Ga,Fe)N: The relationship between structural, electronic, and magnetic properties

“…This diffraction set-up allows us to perform kinetic measurements yielding information on the layer composition, thickness and crystalline quality even on rotating samples, thanks to a recently developed wobbling compensation algorithm. 34,35 Moreover, real time reciprocal space mapping can be carried out in a wide temperature range (20 - Kinetic in-situ XRD measurements were routinely carried out during growth. A full-width-at-the-half maximum (FWHM) analysis of the GaN peak in the in-situ spectra as a function of the growth time, yields information on the crystal quality of the layers.…”

In situ X-ray diffraction during MOCVD of III-nitrides: An optimized wobbling compensating evaluation algorithm

“…Previous works [2] report on an algorithm based on finding the maximum peak position (Pos M ) interpreted as the peak center and the point of reference. The results could be reasonably fitted at high enough spectral intensities expected at large layer thickness.…”

“…However, manufacturing for such high performance products is challenged by reproducibility and material quality constraints that are notably higher than those required for optoelectronic applications. To meet this challenge, we already implemented, to our knowledge the first time, in situ X-ray diffraction (IXRD) for the metalorganic chemical vapor deposition (MOCVD) of III-nitrides as a real-time process tool using a standard X-ray source [2,3].…”

In situ monitoring of periodic structures during MOVPE of III-nitrides

“…Due to the additive number of atomic planes in the growing layer, the detected peak intensity is clearly increasing [13]. The vertical solid line indicates the beginning of the SL deposition starting by switching on the TMAl source.…”

“…By applying X-ray diffraction on grown heterostructures information about layer composition, SL-periodicity and crystalline quality can be deduced. Consequently the use of IXRD during MOVPE represents an additional aspect of a well-established technique which has been demonstrated by several groups [10][11][12][13]. In this section we focus on the kinetic IXRD analysis during growth of GaN/AlGaN SL-structures yielding information about periodicity, layer composition and relaxation.…”