Cl2 chemical dry etching of GaAs under high vacuum conditions—Crystallographic etching and its mechanism

Rate constants for the reaction of atomic and molecular bromine with gallium arsenide

“…This agrees with the findings of Furuhata et al [6] that the etch rate of the (110) cleavage planes is the same as that of the (100) planes.…”

Surface pattern evolution during thermal Cl2 etching of GaAs(001)

“…The etch rates at the end points are 30, 20, 20, and 0 nm/min for ͕111͖B, ͕001͖, ͕011͖, and ͕111͖A surfaces, respectively, consistent with Ref. 8. The remaining free parameter of the parabolic function R() for each grating orientation was obtained by fitting simulated grating shapes to the experimental ones.…”

“…In fact, the following etch rate sequence has been measured by Furuhata et al 8 for different substrate orientations: ͕111͖BϾ͕011͖ϭ͕001͖Ͼ͕111͖A. The sidewalls of our wet etched gratings have angles of 30°Ϯ5°w ith respect to the ͑001͒ surface and thus do not correspond to low-index crystal facets.…”

“…4,6 In order to apply thermal Cl 2 etching to a nanofabrication process such as the definition of quantum wires or dots from a buried heterostructure, 7 it is important to understand how a structured surface evolves during the etch. For thermal Cl 2 etching it was found early on that the etch rates are anisotropic with respect to crystal orientation, 8 and this crystallographic etching limits the achievable pattern transfer. In this study we investigate the evolution of the shape of one-and two-dimensional gratings during thermal Cl 2 etching and devise an optimal strategy for the pattern transfer.…”

Etching temperature dependence of the surface composition and reconstruction for Cl2-etched GaAs layers

“…8 This is because the desorption rate of Ga chlorides is lower than that of As chlorides. 8 This is because the desorption rate of Ga chlorides is lower than that of As chlorides.…”