The novel liquid In precursor DADI (dimethylaminopropyl dimethylindium) has been used to grow multiquantum well structures which show a line splitting, in photoluminescence due to monolayer fluctuations. Moreover, GaInAs-GaInAsP-InP separate confinement multiquantum well modulator structures have been grown. By measuring the quantum confined Stark effect in electroabsorption experiments, a good agreement with theory could be obtained. Thus, it was shown that DADI can be used to grow high-quality heterostructures suitable for optoelectronic devices.<>

This contribution presents the results of growth kinetic studies using trimethylindium-diisopropylamine-adduct ((CH3)3InNHi(C3H7) 2 (TMIAd)) as an indium precursor and dimethylaminopropyl-galla-cyclohexan ((CH2)5Ga(CH2)3N(CH3)2 (APGH)) as Ga source for the LP-MOVPE (low pressure metalorganic vapour phase epitaxy) of GaInAs/InP. For comparison, experiments using the standard sources trimethylindium ((CH3)3In (TMI)) and trimethylgallium ((CH3)3Ga (TMG)) were also carried out. It is shown that GaAs and InP layers with properties comparable to that grown with the standard sources can be grown with these saturated Ga and In compounds. In the case of GaInAs/InP, the dependence of the solid composition on the variation of the V/III ratio demonstrates that the use of the coordinatively saturated group III precursors leads to a reduction of undesired prereactions between the group III compounds and AsH3. This is in contrast to the standard group III sources. In order to achieve lattice-matched growth, quite different Ga/In ratios are necessary because of the different diffusion constants of the group III precursors. The electrical data of the GaInAs/InP layers grown with both saturated or standard group III sources do not show significant differences. This fact, together with the improved growth process, indicates the advantages of the novel group III precursors.

Non-pyrophoric organometallic compounds of aluminum, gallium and indium have been developed for safer application in metalorganic vapor phase epitaxy (MOVPE) of III–V semiconductor layers. They represent molecules which are inter- or intramolecular coordinatively saturated. Their physical properties can be easily varied by simple structure variations. Thus MOVPE precursors are available which are liquid at room temperature and which have already proved to be suitable for use with conventional as well as with new organic group V sources. Synthesis and epitaxy are discussed.

Dimethylaminopropyl-dimethyl-indium (DADI) was used to grow GaInAs and GaInP in combination with two Ga precursors: dimethylaminopropyl-diethyl-gallium (DADEG) and the adduct TMGa-NH/sup i/Pr2. No side reactions with the hydrides could be detected. It is shown that the quality of the layers suffered from the instability of the evaporation rate of DADEG and from some gas-phase reactions between DADI and the Ga-adduct at atmospheric pressure near the substrate surface, although the evaporation rate of DADI is stable over time, as monitored by the composition reproducibility of ternary layers. Due to its lower chemical reactivity DADI can be easily synthesized in high purity, as demonstrated by Hall and photoluminescence (PL) experiments on the layers grown with DADI batches not specially purified.<>

The two novel liquid In precursors TMIn-HNiPr2 and (3-dimethylaminopropyl)dimethylindium (DADI) were synthesized and their behaviour in the MOVPE growth of InP studied. Layers with low temperature mobilities in excess of 100,000 cm2/V·s could be grown. When growing GaInAs, some side reactions between TMIn-HNiPr2 and AsH3 were observed, which did not significantly affect the layer quality. DADI could be used in combination with tertiarybutylphosphine resulting in acceptable InP quality at moderate growth temperatures.

This contribution presents the results of growth kinetic studies using trimethylindium-diisopropylamine adduct as an In precursor and isopropylphosphine as a group V source for the MOVPE (metalorganic vapor phase epitaxy) of InP. For comparison, experiments using the standard sources trimethylindium and PH3 and combinations of both approaches were also performed. From the dependence of the growth rate on temperature it can be concluded that specifically the use of the organic P source with TMI may lead to a pronounced reduction of the rate due to parasitic reactions involving both precursors. The coordinatively saturated adduct is a suitable reaction partner for the organic P precursor with respect to reducing prereactions. For all material combinations satisfactory electrical and luminescence properties of the InP layers were obtained.

Intramolecularly base-stabilized four-coordinated metallacyclic organoaluminium, -gallium, and -indium compounds C5H10Al(CH2)3NMe2 (4), C4H8Ga(CH2)3NMe2 (5), C5H10Ga(CH2)3NMe2 (6), C5H10GaCH2CH(Me)CH2NMe2 (7), C4H8Ga(CH2)4NMe2 (8), C5H10Ga(CH2)4NMe2 (9), EtAl[(CH2)3]2NMe (10), MeGa[(CH2)3]2NMe (11), EtGa[(CH2)3]2NMe (12), MeIn[(CH2)3]2NMe (13), and MeIn Activated (CH2)3N(Me)CH2CH2N(Me)(CH2)2CH2 (14) have been synthesized by the reaction of [3-(dimethylamino)propyl]aluminium dichloride (1), [3-(dimethylamino)propyl]gallium dichloride (2), [3-(dimethylamino)-2-methylpropyl]gallium dichloride (3), or [4-(dimethylamino)butyl]gallium dichloride with the respective bis-Grignard reagents or by the reaction of the organometal dichlorides RMCl2 with bis[3-(chloromagnesio)propyl[methylamine or with N,N'-bis[3-(chloromagnesio)propyl]-N,N'-dimethylethylenediamine. Aluminium or gallium trichloride reacts with tris[3-(chloromagnesio)propyl]amine to give Al[(CH2)3]3N (15) and Ga[(CH2)3]3N (16). The H-1, C-13-NMR and mass spectra of the new compounds as well as the X-ray crystal structure of 16 are discussed. 4, 6, and 12 have been tested successfully as MOVPE precursors.

AbstractIntramolecularly stabilized four‐coordinated organoaluminium, ‐gallium, and‐indium compounds R2MC6H4CH2NR'2‐(2) (1–7), Me2MCH2C6H4NMe2‐(2) (8, 9), Me2MCH2C6H4CH2‐NMe2‐(2) (10, 11), and Me2GaC6H4NMe2 (12) have been synthesized from O ‐[(dialkylamino)methyl]phenyllithium, [O ‐(dimethylamino)phenyl]methyllithium, {O ‐[(dimethylamino)methyl]phenyl}methyllithium and O ‐(dimethylamino)phenyllithium, respectively. The 1H‐, 13CNMR, and mass spectra of the new compounds and the X‐ray crystal structures of 2 and 7 are reported and discussed.

The MOCVD of AlGaAs and GaAs from coordinatively saturated group III source materialsi.e. 1–3-dimethyl-aminopropyl-l-galla-cyclohexane ((C5H10)Ga(C2N(CH3 2) and the corresponding Al compound) was investigated. It was demonstrated that these precursors, which are inherently free of alkoxy contamination, are suitable for epitaxial growth of GaAs layers and structures of GaAs/AlGaAs. For comparison, data achieved with TEA (Al(C2H5)3) or TiBA (Ali(C4H9)3) and TEG (Ga(C2H5)3) are presented. A basic finding of this study is that due to the low thermal stability of TEA, TiBA and TEG the layers grown from these compounds suffer from insufficient homogeneity of layer thickness and composition. In contrast, the coordinatively saturated compounds show a reactivity suitable for large area growth. Additionally, intrinsic impurity (N, C) uptake appears to be low and electrical as well as PL data show the satisfactory quality of GaAs and AlGaAs layers grown from this new type of precursors. Specifically, a reduction of oxygen incorporation compared to growth from the standard trialkyls is indicated by PL measurements on layers grown at different temperatures.

The use of the non-pyrophoric III-molecules (Dimethylamino-propyl-Galla-cyclohexane and the corresponding Al-compound) for the growth of (AlGa)As/GaAs quantum well and modulation-doped heterostructures by low-pressure MOVPE has been investigated. Heterostructures with electron concentrations between 9*10(11) and 4*10(12) cm-2 and high electron mobilities between 5800 and 3000 cm2/Vsec at room temperature under optimized conditions are grown in combination with AsH3 as well as with the AsH3-substitute tertiary-butylarsine (TBAs). Prereactions of SiH4 and TBAs are observed, leading to higher Si-dopant incorporation, as is also established for growth using standard alkyl-111-compounds.

The Ga sources 1-3-dimethyl-aminopropyl-1-galla-cyclohexane (C5H10Ga-(CH2)-N(CH3)2) and trimethylgallium-diisopropylamine adduct (Ga(CH3)3…Ni(C3H7)2H) were succesfully utilized for the epitaxial growth of GaAs in low pressure (1000–2000 Pa) MOCVD. AsH3 was used as the group V source. GaAs layers obtained from these novel precursors at optimized conditions exhibit good morphological qualities. Electrical and photoluminescence data indicate that the intrinsic impurity (C,N) uptake from the source materials is low.

A new class of non-pyrophoric and almost air-resistant organometallic compounds of indium, aluminium and gallium has been synthesized for more convenient and safer application in vapour phase epitaxy of III–V semiconductor layers (metal-organic chemical vapour deposition (MOCVD)). It is represented by molecules which are intramolecularly and coordinatively saturated. By simple structure variations such physical properties as the melting point, boiling point and vapour pressure can be easily varied. Thus compounds are available, which are liquid at room temperature and have a vapour pressure which is high enough for MOCVD without additional heating of the source. Synthesis and initial epitaxy results are discussed.

Dimethyl (3-dimethylaminopropyl) indium was synthesized and used for the first time as an indium source for the growth of InP layers by metalorganic vapor phase epitaxy at atmospheric pressure. This compound is liquid at room temperature with a vapor pressure of 30–40 Pa at 30 °C, which enables its use at low source temperatures. The layers were grown at a bubbler temperature of 30 °C. The growth temperature was varied between 580 and 660 °C. Hall measurements revealed good electrical data with carrier mobilities up to 49 900 cm2 /V s at 77 K. Temperature-dependent photoluminescence experiments confirmed these results and indicated that zinc was the main residual acceptor impurity.

This paper presents proposals for the synthesis of several group III metal organics (In, Ga, Al compounds) and preliminary results on their use in the MOVPE (metal organic vapor phase epitaxy) of III-V semiconductors. The common feature of all these precursors is that they are saturated by interor intramolecular coordination. They are even non-pyrophoric and air resistant which is an interesting aspect with respect to safe handling. In addition, the compounds are liquid at room temperature with a low but sufficient vapor pressure for MOVPE without additional heating of the source.