A rapid reflectance-difference spectrometer for real-time semiconductor growth monitoring with sub-second time resolution

作者：Nunez Olvera O^*; Balderas Navarro R E; Ortega Gallegos J; Guevara Macias L E; Armenta Franco A; Lastras Montano M A; Lastras Martinez L F; Lastras Martinez A

来源：Review of Scientific Instruments, 2012, 83(10): 103109.

DOI：10.1063/1.4760252

We report on a rapid, 32-channel reflectance-difference (RD) spectrometer with sub-second spectra acquisition times and Delta R/R sensitivity in the upper 10(-4) range. The spectrometer is based on a 50 kHz photo-elastic modulator for light polarization modulation and on a lock-in amplifier for signal harmonic analysis. Multichannel operation is allowed by multiplexing the 32 outputs of the spectrometer into the input of the lock-in amplifier. The spectrometer spans a wavelength range of 230 nm that can be tuned to cover E-1 and E-1 + Delta(1) transitions for a number of III-V semiconductors at epitaxial growth temperatures, including GaAs, InAs, AlAs, and their alloys. We present two examples of real-time measurements to demonstrate the performance of the RD spectrometer, namely, the evolution of the RD spectrum of GaAs (001) annealed at 500 degrees C and the time-dependent RD spectrum during the first stages of the epitaxial growth of In0.3Ga0.7As on GaAs (001) substrates.

• 出版日期2012-10