Fabrication of high quality two-dimensional electron gases by overgrowth of focused ion beam implantation doped AlxGa1−xAs

Fabrication of submicrometer patterned two-dimensional electron gases by overgrowth of focused ion beam doped AlxGa1−xAs

“…Here, the desired pattern is implanted employing a Si dose that results in a 2DEG with suitable electron density. 10,11 After the Si implantation that defines the 2DEG regions, optical visible alignment marks are sputtered with Au + ions employing doses of approximately 10 16 cm −2 . These marks allow for mask alignment in subsequent processing steps such as mesa etching or contact metallization.…”

“…9 We have used a similar approach and were able to increase the maximum electron mobility at 4.2 K to 1.5ϫ 10 6 cm 2 /V s in extended 2DEGs by optimizing the process, especially including a high temperature annealing step before regrowth. 10,11 Another approach is the use of a FIB column directly integrated in the MBE growth chamber. [12][13][14][15] With this approach, high quality 2DEGs and 2DHGs have been realized.…”

Formation of patterned Ga InAs/GaAs hetero-structures using amorphous arsenic mask

“…The amorphous As layer can be removed easily by annealing it at about 350 1C in UHV environment [2]. Many investigators have examined about properties of the amorphous As layer for the use of passivation layer [3][4][5][6][7]. Further, using the amorphous As layer as a mask, photolithographic patterning was achieved by Husby et al [8].…”

Laterally patterned high mobility two-dimensional electron gases obtained by overgrowth of focused ion beam implanted Al1−Ga As

“…The 2DEG is thus conÿned to the non-etched mesa regions and has a non-planar topography. Focused ion beam (FIB) implantation doping in combination with MBE is a promising technique for the fabrication of laterally patterned 2DEGs in a bottom-up approach [1][2][3]. 2DEGs with electron mobilities up to 1:5 × 10 6 cm 2 =V s have been achieved by this method [3].…”