Movpe Growth of GaInP/AlGaInP Heterostructure for Visible Laser

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ABSTRACT The GaInP/AlGaInP heterostructure was grown on (100) GaAs substrate using low pressure metal-organic vapor phase epitaxy(LP MOVPE). The growth temperature and pressure were held constant at 740 0 C and 40 torr, respectively. The GaInP multiquantum well layers from 10 A to 85 A were lattice matched to the substrate. High resolution transmission electron microscopy and low temperature photoluminescence measurements indicated that the GaInP/AlGaInP well layers were uniform in thickness and that the interface was abrupt and free of defects. For high performance of visible laser diodes, highly doped p-AlGaInP layer(8X10 1 7 /cm3 ) was obtained. It was also found that the Zn acceptor concentration increased with growth rate. In this study, the GaInP/AlGaInP laser diode, 645nm and 20mW, was fabricated by employing multiquantum well and highly doped p-cladding layer. Keywords: visible laser, GaAs, GaInP/AlGaInP,

quantum well

l. Introduction The visible laser diode of GaInP/AlGaInP has been developed extensively as light sources for high density optical disk recording, laser beam printer, and barcode reader. High quality GaInP/AlGaInP structures reported recently have been grown mostly by MBE(Molecular Beam Epitaxy)[1] and MOVPE(Metalorganic Vapor Phase Epitaxy)[2-4). Device performance is known to be strongly affected by the electrical properties of AlGaInP layers, especially the p-type layers. High Al content cladding layers are required for enhanced electron and photon confinements in the GaInP/AlGaInP heterojunction. However, a problem associated with AlGaInP layer is the high electrical resistivity due to low Zn incorporation efficiency. A highly doped p-type cladding layer can lead to low resistivity and reduce the electron current flow from the active layer to the p-cladding layer owing to the relatively small band discontinuity in the conduction band[5]. The AlGaInP growth on misoriented substrates is known to suppress the spontaneous ordering of crystal, thereby increasing bandgap energy and carrier concentration in the p-cladding layer(6]. In this study, the structural and optical properties of GaInP/AlGaInP quantum well layers grown by MOVPE on 70 of f (100) GaAs substrate toward [011] direction was investigated. Also, effects on growth rate by Zn acceptor incorporation in (AI0. 7 Ga 0 . 3 ) 0 . 5 In 0 . 5 P layer was discussed. The short 365 Mat. Res. Soc. Symp. Proc. Vol. 326. ©1994 Materials Research Society

wavelength(645nm) laser diode of GaInP/AlGaInP grown on 7° off (100) Si-doped GaAs toward [011] direction was fabricated by employing multiquantum well and highly doped p-cladding layer.

2.Experiment The GaInP/AlGaInP epitaxial growth was performed on (100) GaAs and 7* off (100) Si-doped GaAs toward [011] direction. Horizontal reactor with by-pass/reactor gas line system was used for rapid gas switching. The growth temperature and pressure were 740 °C and 40 torr, respectively. TEGa, TMAI, TMIn, 100% PH3 , and 100% AsH3 were used as source materials. DEZn and SiH4 (0.1% in H2) were used as do