In this study, the use of novel, liquid, organic arsenic precursors as substitutes for the highly toxic hydride gas arsine (AsH3) in low pressure metalorganic vapor phase epitaxy (LP-MOVPE) of (GaIn)As lattice matched on InP has been investigated. The model precursors out of the classes of (alkyl)3-nAsHn (n = 0,1,2) are tertiarybutyl arsine (TBAs), ditertiarybutyl arsine (DitBAsH) and diethyltertiarybutyl arsine (DEtBAs). The MOVPE growth has been investigated in the temperature range of 570–650°C using VIII ratios from 2 to 20. The obtained epitaxial layer quality as examined by means of optical and scanning electron microscopy (SEM), high resolution double crystal X-ray diffraction, temperature-dependent van der Pauw-Hall, as well as photoluminescence (PL) measurements, will be compared for the different source molecules. Under optimized conditions almost uncompensated n-type (GaIn)As layers with carrier concentrations below 1 × 1015 cm−3 and corresponding mobilities above 80 000 cm2/V · s have been realized. For TBAs and DitBAsH in combination with the corresponding P sources TBP and DitBuPH, respectively, we have worked out a process parameter area for the growth of layers with device quality, as proven by the realization of a pin-detector structure.

In this work the use of the novel ditertiarybutyl-phosphorous and arsenic precursors for low pressure metalorganic vapor phase epitaxy (LP-MOVPE) application with respect to InP/(GaIn)As-heterostructures and pin-detector device structures has been studied. Layer quality has been investigated by means of optical and scanning electron microscopy, temperature dependent van der Pauw-Hall measurements, temperature dependent luminescence measurements, high resolution double crystal X-ray diffraction, XRD- and PL-mappings, CV-depth profiling and SIMS measurements. The InP/(GaIn)As-multi quantum well heterostructures exhibit narrow XRD-linewidths of both the main reflection peak as well as the superlattice satellite peaks down to the theoretical limit. The n-type background doping-level of the (GaIn)As layers is reduced to 2×1015 cm-3 for optimized growth conditions. The low temperature luminescence is characterized by intense and narrow exciton transitions (2-3 meV FWHM). A InP/(GaIn)As-layer structure has been processed to planar pin-diode detector structures of 55 μm diameter. The devices show dark currents in the range of 1-1.5 nA at a reverse bias of -5 V. The distribution of the I/U-characteristic is homogeneous over the entire processed wafer area. The device yield exceeds 95%

We describe methods of improving the metalorganic vapour phase epitaxy (MOVPE) growth of heteroepitaxial GaAs on Si. The low temperature growth step at the start is optimized by using the new alternative group III precursor dimethylethyl-amine-gallane (GaH3·N(CH3)2C2H5 (DMEAGa)) as a substitute for the conventional group III compound TMGa. Further improvements in surface morphology and X-ray diffraction linewidth are obtained by applying the modulated atomic layer epitaxy (ALE) for this growth step. Thermal cycle annealing which is much more effective in dislocation reduction than constant temperature annealing has been optimized with respect to the high as well as the low temperature steps. We present a model of low temperature behaviour of dislocations to explain the role of cooling the samples during thermal cycle annealing. An additional improvement of layer quality is achieved by introducing a thin (AlGa)As-layer after the low-temperature-GaAs-layer leading to a confinement of dislocations after performing thermal cycle annealing as established by TEM-investigations.

New group III hydride precursors have been synthesized in high yield and their purities have been measured by atomic absorption spectroscopy analysis, ion chromatography and metal-organic vapour-phase epitaxy. With these compounds, which have no metal-to-carbon bond, a decrease in carbon incorporation into (Al, Ga)As/GaAs heterostructures is achieved. The efficient combination of these sources with organoarsines at lower V-to-III ratios allows for a replacement of the highly toxic AsH3 by new alternative group V precursors, which show remarkable lower toxicities.