Dependence of the density and type of stacking faults on the surface treatment of the substrate and growth mode in ZnSxSe1−x/ZnSe buffer layer/GaAs heterostructures

Abstract

A systematic dependence of the density and type of stacking fault defects with substrate surface chemistry and film growth mode was observed in ZnSe-based films grown on GaAs substrates. Namely, the density of Frank-type stacking faults is very large for films grown on Ga-rich surfaces, but is very low for films grown on As-stabilized surfaces exposed to Zn prior to the growth of the film. In contrast, the density of Shockley-type stacking faults increases for films grown by 3D growth mode at the initial stages of growth, but decreases greatly if the films are grown by the layer-by-layer growth mode. Films with stacking fault densities as low as 104/cm2 were obtained by growing the films by the layer-by-layer growth on GaAs epilayers with As-stabilized surfaces that were exposed to Zn for 1–2 min prior to the growth of the films.

MBE growth of MgS nanowires characterized using AFM

“…GaAs (0 0 1) substrates were etched in a 2:2:15 H 2 O 2 :H 2 O:H 2 SO 4 solution prior to entry into the growth chamber. The oxide layer was removed by rapid heating to 580 1C before cooling back down to the growth temperature of 260 1C under a Zn flux [4]. Contamination of the substrate by sulphur during oxide removal was avoided by reducing the ZnS source temperature by 80 K during the cleanup and using a liquid nitrogen cooled shutter in front of the cell [1].…”

Development of surface structures in MBE grown MgS and the origin of the phase instability

“…GaAs (001) substrates were etched in H 2 O 2 :H 2 O:H 2 O 2 SO 4 solution prior to being degassed and transferred into the growth chamber. The oxide layer was then removed by heating to ~580 °C before cooling to the growth temperature (typically 240-270 °C) under a Zn flux [2]. Prior to the growth of the MgS layer, a 50 nm ZnSe buffer layer was deposited in order to protect the substrate from S contamination.…”

The use of atomic hydrogen for substrate cleaning for subsequent growth of II-VI semiconductors

“…An ongoing problem has been a high density of defects related to stacking faults originating at the substrate-epilayer interface. The defects serve as nucleation sites for dislocation generation during device operation, leading to degradation and ultimate device failure in an unacceptably short time2 -11 It is believed that the stacking faults occur during initial layer growth2 , 12 The stacking faults are either due to incomplete oxide removal or poor surface preparation that induces the formation of stoichiometry-related defects. For molecular beam epitaxy (MBE) growth of ZnSe on GaAs substrates, the final step prior to growth is often a thermal cleaning at temperatures ranging from 580 to 650~ to remove the native *myersC/~vvu.edu (Received October 24, 1996; accepted February 15,1997) oxides.IS.…”