Etching of GaAs(100) by Activated Hydrogen

Abstract

Etching of oxidized GaAs(100) wafers by activated hydrogen is shown to be very effective. The oxide can be removed by the reaction of hydrogen with the sample at room temperature and a hot filament present in front of the sample surface. The oxide removal at the surface was controlled via X-ray photoelectron spectroscopy (XPS) and low-energy electron diffraction (LEED). After a number of cleaning cycles with hydrogen, a (1 x 1)-LEED-pattern is observed. The results clearly demonstrate that activated hydrogen is an interesting candidate for surface cleaning prior to further processing.

Analysis of mechanism of carbon removal from GaAs(100) surface by atomic hydrogen

“…1 similar effect is observed-the carbon sp2 signal at 252 eV does not decrease to noise level but oscillates around the saturation level (shown as straight line). From the above-presented considerations one can draw the conclusion that the reduction of carbon contamination by atomic hydrogen proceeds via the formation of hydrocarbons and subsequent desorption of the reaction products, as commonly supposed in the literature [8][9][10][11][12][13]39]. Moreover, this transformation is not rate limited since an exponential-like behavior is observed even in the presence of a substantial amount of hydrocarbons at the surface.…”

“…However, even if it is clear that hydrocarbons are the reaction products, there is no clear evidence for the specific form of the hydrocarbon [8,14,39]. Thus, in order to identify the reaction products upon the atomic hydrogen irradiation we have performed mass spectrometry during the treatment of the EPI sample.…”

Surface Preparation of InAs (110) Using Atomic Hydrogen

“…This is qualitatively consistent with the information given by comparing the as-loaded spectra of the As 3d and As 2p 3/2 photoelectrons and considering their different inelastic mean free paths. The lower kinetic energy (higher binding energy) As 2p 3/2 electrons have a mean free path of ~ 7.5 Å (Schaefer et al 1990), compared with the ~ 27.5 Å of the higher kinetic energy (lower binding energy) As 3d electrons. Because of the exponential attenuation, over 98 % of each signal comes from within four mean free path lengths of the surface.…”

“…where I s0 is the unattenuated clean surface signal obtained after AHC, z is the thickness of the oxide layer, and λ is the inelastic mean free path of the As 3d photoelectrons 27.5 Å (Schaefer et al 1990). Allowing for the error associated with determining the peak areas, this gives an oxide layer thickness of 30 ± 5 Å.…”

Hydrogen cleaning and smoothing of semiconductor surfaces: The case of II–VI compounds

“…1,2 The cleaning process is based on the desorption of chemisorbed and physisorbed species such as oxides and carbon which form volatile compounds after chemical reactions with hydrogen radicals. Experiments have been reported for silicon, 3 III-V 1 and II-VI 4,5 compounds, employing either electron cyclotron resonance ͑ECR͒ plasma sources or thermal cracker ͑ThC͒ cells.…”