Improved dosimetry for metalorganic vapor phase epitaxy from a solution of trimethylindium

Abstract

A novel precursor system for metalorganic vapor phase epitaxy of indium-containing layers, solid trimethylindium (TMI) partly dissolved in N, N-dimethyldodecylamine, is described. Used in a conventional bubbler, the output concentration of TMI entrained by H2 carrier gas from this source was measured using an ultrasonic cell (Epison) and compared with that from a conventional TMI source. Initially the output stability from both sources was found to be virtually identical; after approximately 50% depletion the output from the solution source was substantially more stable. The solution source was used to deposit InP and lattice-matched InGaAs/InP, with excellent optical and electrical properties (μ77=181 000 and 44 000 cm2/V s, respectively). With only 5 g solid TMI remaining, the continued stability of the solution source was shown by growing a lattice-matched GaInAs/InP layer having an x-ray diffraction peak of 26 arcsec.

Developments in CVD Delivery Systems: A Chemist’s Perspective on the Chemical and Physical Interactions Between Precursors

“…Excess TMIn is added to the initially formed 1:1 TMIn-dmda adduct-solution. [49,50] Even when only 5 g of solid TMIn remains, the performance of the system is satisfactory. This method is of renewed interest as it may provide a source of very low oxygen-containing TMIn.…”

“…One commonly used approach, as mentioned before, is to use two bubblers in series since this allows for greater contact time between the entraining gas and the solid precursor and can, hence, lead to more reproducible mass transport results. Another approach, initially developed by Frigo and co-workers, [49,50] is to use a saturated solution of TMIn in a non-volatile coordinating solvent that is in contact with the solid precursor, Figure 12. The advantage of this approach is that the carrier gas passes through a solution containing dissolved precursor, making equilibration easier than for the solid vapor contact.…”