Title :
Growth of Si and Ge nanostructures on Si substrates using ultrathin SiO2 technology
Author :
Ichikawa, Masakazu
Author_Institution :
Joint Res. Center for Atom Technol., Ibaraki, Japan
fDate :
8/1/2002 12:00:00 AM
Abstract :
Using scanning reflection electron microscopy and a high-temperature scanning tunneling microscopy (STM), we study the growth processes of Si and Ge nanostructures on Si substrates covered with ultrathin SiO2 films. Si windows are formed in the ultrathin SiO2 films by irradiating focused electron beams used for SREM or field emission electron beams from STM tips before or during heating samples. Ge nanoislands are grown only at the Si window positions by depositing Ge on the samples and by subsequent annealing of them. Moreover, Ge nanoislands about 7 nm in size and ultrahigh density (>1012/cm2) are grown on the ultrathin SiO2 films. These nanoislands can be manipulated by STM when they are separated from Si substrates by the ultrathin SiO2 films. Si, Ge, Ge/Si and Si/Ge/Si nanoislands can also be grown on the Si windows by selective growth using Si2H6 and GeH4 gases. These nanoislands are found to be stable on the Si windows during high-temperature annealing. These results indicate that ultrathin SiO2 technology is useful for growing Si and Ge nanostructures on given areas.
Keywords :
annealing; elemental semiconductors; germanium; island structure; nanostructured materials; nanotechnology; reflection high energy electron diffraction; scanning electron microscopy; scanning tunnelling microscopy; self-assembly; semiconductor epitaxial layers; semiconductor growth; silicon; vapour phase epitaxial growth; 7 nm; Ge; Ge nanoislands; Ge nanostructures; Ge-Si; Ge/Si nanoislands; GeH4; GeH4 gases; SREM; STM tips; Si; Si nanoislands; Si nanostructures; Si substrates; Si windows; Si-Ge-Si; Si/Ge/Si nanoislands; Si2H6; Si2H6 gases; SiO2; annealing; field emission electron beams; focused electron beams; growth processes; heating; high-temperature annealing; high-temperature scanning tunneling microscopy; scanning reflection electron microscopy; selective growth; self-assembling technique; size; ultrahigh density; ultrathin SiO2 technology; Annealing; Electron beams; Gases; Heating; Nanostructures; Optical films; Optical reflection; Scanning electron microscopy; Semiconductor films; Tunneling;
Journal_Title :
Quantum Electronics, IEEE Journal of
DOI :
10.1109/JQE.2002.800972