Spectroscopic process sensors in MOVPE device production

Development and control of MOVPE growth processes for devices using reflectance anisotropy spectroscopy and normalized reflectance

“…The resulting diagrams give a distinctive fingerprint of the entire growth process since the RA signal is sensitive to the important layer properties like the doping concentration [12,13] of the respective layer and the reflectance gives access to growth rate and layer composition. Figure 1a shows a RA color-plot taken during a complete growth run for a HBT device [4] pared to that of Fig. 1a.…”

“…Therefore the continuously measured RA and NR spectra are usually color-coded [4] in order to display the fully 4-dimensional measurement (RAS, R/R ref , growth time, wavelength, see, e.g., Figs. 1 and 3).…”

“…Processes and in situ measurements related to HBTs [4], EELs [5] as well as to VCSELs [6] are discussed. The possibility of controlling the composition even of quaternary materials such as InGaAsP [7] and AlGaInP [8] is highlighted in the last part of this paper.…”

MOVPE growth of (Al, Ga)InP-based laser structures monitored by real-time reflectance anisotropy spectroscopy

“…11,12 It is based on the configuration of Aspnes et al 7 The RAS setup is mounted above the reactor tube of the epitaxial system, and has optical access to the sample through a standard normal incidence viewport made out of quartz transparent to UV/VIS-light. Apart from a tiny hole in the liner tube no modification to the growth system is necessary.…”

Application of reflectance anisotropy spectroscopy to laser diode growth in MOVPE

“…Undoped AlGaAs layers have intensively been studied using RAS [4], while doped AlGaAs layers are studied only marginally [5]. More results are available for the dependence of the RA on doping of GaAs [6][7][8][9].…”