GaAs substrates for the MOVPE growth of (Hg,Cd)Te layers

Abstract

After a review of the structural properties of (Hg,Cd)Te layers grown by MOVPE on GaAs substrates, topical questions such as out-diffusion of Ga and As from the substrate into the layers, monolithic integration of signal processing into the substrate and the presence of pyramidal defects in (100) layers will be discussed. In order to solve the last problem, a systematic study of the influence of the (hl 1) GaAs substrate orientation and polarity on the structural properties and surface morphology of CdTe layers grown by MOVPE has been carried out. Twin-free layers are obtained on (211)A, (311)B and (511)B GaAs surface orientations as explained by a model taking into account the type of dangling bonds at the interface. The performance of photoconductors fabricated on (Hg,Cd)Te layers of various orientations confirms these results. Particularly good results have been obtained for the (31 l ) B orientation.

Study of Te aggregation at the initial growth stage of CdZnTe films deposited by CSS

“…Specimens for cross-sectional TEM analyses were prepared by cutting and mechanical grinding down to 50-60 µm, followed by Ar ion beam milling using a FISCHIONE 1010 Ion Mill to form small holes. All TEM images were taken down [1][2][3][4][5][6][7][8][9][10] zone axis with a Tecnai F30 G2 transmission electron microscope at 300 kV.…”

One-step fast deposition of thick epitaxial CdZnTe film on (001)GaAs by close-spaced sublimation

“…Hillocks and dual-epitaxy (film with two competitive orientations) are frequently observed in poor epitaxial CdZnTe films. 4,18,[23][24][25] Hillocks form because of the penetration of the stacking faults in the film to the surface, 26 while the stacking fault energy in CdZnTe is rather low. 27 As far as dual epitaxy, films can be either (111) or (001) oriented, 24,25,28 or sometimes even oriented with both directions 18 on (001)Si or (001)GaAs.…”