Metalorganic vapor phase epitaxial grown heterointerfaces to GaInP with group-III and group-V exchange

AlGaAs/InGaP interfaces in structures prepared by MOVPE

“…Such an As/P exchange was observed in the InGaP/GaAs interfaces [6,7] and also in other ones [14,15]. The thickness of a transition layer formed by the process varied with growth conditions.…”

“…Although In 0.485 Ga 0.515 P/ GaAs is an attractive system, it has not met the expectations due to problems linked with the ordering effect [5] and due to problems linked with the complexity of the InGaP/GaAs interface. The former is caused by the self-organisation of Ga and In atoms at the grown surface and the latter by an As/P exchange process [6,7]. The former effect leads to the formation of ordered domains and to a reduction of the band gap and the latter lowers the quality of the InGaP/GaAs interface, which is always worse than the quality of the AlGaAs/GaAs interface despite growth optimisation efforts [16,17].…”

Evaluation of the composition of the interlayer at the inverted interface in InGaP/GaAs heterojunctions

“…In the literature basically two compounds have been proposed to be the interlayer alloy, i.e., In x Ga 1−x As [8,14,18,19] and In x Ga 1−x As 1−y P y [7,8,10,13,20,21]. The formation of either one of these two compounds has been reported to be strongly affected by the growth conditions, such as growth interruption or not, duration of the PH 3 purge after stopping the growth of InGaP, duration of the As H 3 pre-flow before TMGa is introduced, intentional interposition of some extra layer etc [7,8,10,13,14,[18][19][20][21].…”

“…InGaP/GaAs has a low conduction band offset that makes it very suitable for HBTs [9]. However, the InGaP/GaAs system has the drawback that an extra interlayer spontaneously forms at the GaAs-on-InGaP interface (inverted interface) [7][8][9][10][12][13][14][15][16][17][18][19][20][21]. The causes suggested in the literature for its formation are three: In carry-over, As/P exchange and P/As intermixing at the location of the inverted interface [7][8][9][10][12][13][14][15][16][17][18][19][20][21].…”

“…Besides PL, several other techniques, like X-ray diffraction [12,16,[18][19][20], electrical methods [24,25] scanning tunneling spectroscopy [26] were employed to investigate the properties of the interlayer at the GaAs-on-InGaP interface. Transmission electron microscopy (TEM) was applied in some works to get information on the overall structure of the InGaP/GaAs samples [6,8,19,20,27,28], but detection and information right of the interlayer was not reported apart from the paper by Hsieh et al where the interlayer was detected by Scanning TEM (STEM) [7]. However, the exact identification and evaluation of the interlayer composition by TEM seems to be missing.…”