Selective epitaxial growth of dot structures on patterned Si substrates by gas source molecular beam epitaxy

Abstract

Selective epitaxial growth of Ge dot structures is investigated to obtain highly regular dot arrays with excellent size uniformity in the nanoscale. The dot structures are grown in patterned fine windows ranging in diameter from 650 to 90 nm on Si(100) substrates covered with SiO 2 masks. The dimensions and number of the dots grown in a window significantly change depending on window size, growth temperature and time and the thickness of the Si buffer layer. These growth characteristics are considered to be induced by the Stranski-Krastanov growth mode and migration mechanism of Ge atoms on Si substrates. It is noted that Ge dots whose diameter is much smaller than the pattern size are formed with high uniformity and that the position is precisely controlled by SEG. The Ge dot structures are found to give rise to prominent luminescence with well separated phonon replicas and the energy position systematically changes when the growth conditions are varied.

Fabrication technology of SiGe hetero-structures and their properties

“…Combination of selective epitaxial growth (SEG) and electron beam (EB) lithography is a promising approach to sufficiently control the dots [211,212]. As mentioned before, GSMBE has an advantage to provide selectivity between Si and SiO 2 surfaces and Ge dots can be grown only on Si surfaces.…”

Energetics of Ge nucleation on SiO2 and implications for selective epitaxial growth

“…Other applications include ordered arrays of quantum dots [8][9][10][11][12] for photodetectors [13] and quantum cellular automata [14]. The SEG technique has also been used in conjunction with epitaxial lateral overgrowth [15][16][17] to define areas of low-defect-density films lattice-mismatched to the underlying substrate.…”

Absence of island–island interaction during formation of isolated Ge islands in small windows

“…[1][2][3][4][5][6][7][8][9] For such devices positioning of Ge dots of desired size at predefined precise locations is very important. [1][2][3][4][5][6][7][8][9] For such devices positioning of Ge dots of desired size at predefined precise locations is very important.…”