Ethylaluminum dichloride AlEtCl2
n-Propylaluminum dichloride AlnPrCl2
AlEtCl2, AlnPrCl2 for Al2O3 MOCVD
Ethylaluminum, propylaluminum dichlorides (EtAlCl2, nPrAlCl2) were used as precursors for the MOCVD growth of Al2O3 thin films on Si and GaAs; the films were characterized by IR, x-ray spectroscopies and electrical measurements [352]
Methylaluminum dichloride diethyletherate AlMeCl2(Et2O)
Ethylaluminum dichloride diethyletherate lEtCl2(Et2O)
AlMeCl2(Et2O), AlEtCl2(Et2O) for (Ti,Al)(O,N) by PECVD
AlMeCl2(Et2O) and AlEtCl2(Et2O) (with TiCl4 and H2 as co-reactants) have been applied for the growth of (Ti,Al)(O,N) coatings by PECVD. [4]
Diethylaluminum chloride AlEt2Cl
Diethyl Aluminum Chloride (DEACl) [AlEt2Cl]2 is a dimer with 3-center 4-electron bonds.
It has been synthesized by the reaction of aluminum metal with alkylhalides:
2 Al + 4 RX → AlR2 (μ-X)2AlR2
(This species is in equillibrium with RXAl(μ-X)2AlRX; X = halide) (less favoured species)
Vapor pressure of diethylaluminum chloride AlEt2Cl was measured by capacitance manometer at temperatures 5?°C to 60°C. [351] (AlEt2Cl)2 has vapor presure 3.0Torr / 60°C.
AlEt2Cl for Al metal CVD
[AlEt2Cl]2 has been applied for the deposition of Al metal on Si substrates in cold-wall reactor at temperatures 313–380 °C(usual growth temperature is 340°C) in the H2 carrier (precursor was evaporated at 60°C). The growth rate of Al films was 37 nm/min, resistivity was 5.1 μΩcm, activation energy was 39 kcal/mol.
Mechanism of decomposition during growth on Si is following:
AlEt2(μ-Cl)2AlEt2 → AlCl + 2 Et2 (Al-subchloride)
4 AlCl + Si → 4 Al + SiCl4
On Ge / GeAs disproportionation happens: 3 AlCl → AlCl3 + 2 Al
AlEt2Cl, AlnPrCl, for Al2O3 MOCVD
Diethylaluminum, dipropylaluminum chlorides (Et2AlCl, nPr2AlCl) were applied as precursors for the growth of Al2O3 thin films on Si and GaAs substrates by MOCVD; the films were characterized by IR, x-ray spectroscopies and electrical measurements. Thermal decomposition of dipropylaluminum chloride was investigated by thermal analysis [352]
AlEt2Cl for AlGaAs MOCVD
Diethyl aluminum chloride Et2AlCl in combination with diethyl gallium chloride were successfully employed as precursors for the epitaxial growth of AlxGa1–xAs. The composition, thickness, and compositional uniformity of these layers were strongly dependent on the growth temperature, as determined with double-crystal XRD and photoluminescence measurements; the observed trends were explained using a thermodynamic model based on the free energy minimization of the expected gas and solid phase constituents. Correct choice of growth conditions allowed to grow selectively AlxGa1–xAs on GaAs wafers masked with SiO2 or Si3N4. Selectivity of AlxGa1–xAs improved with decreasing diethyl aluminium chloride mole fraction and with increasing temperature, in accordance with thermodynamic considerations. AlAs growth was not selective. [353]
(C2H5)2AlCl, in combination with (C2H5)2GaCl , have been applied for selective MOVPE (selective epitaxy, SE) of AlxGa1-xAs layers used for the formation of small sub-micron SE laterally defined hetero-structures. [[i] ]
[i] Thomas F. Kuech, Journal of Crystal Growth, Volume 115, Issues 1-4, 2 December 1991, Pages 52-60, “ The use of chloride based precursors in metalorganic vapor phase epitaxy”