Properties of solution TMI as an OMVPE source

Solid trimethylindium (TMI) is the precursor of choice of the vast majority of MOVPE applications for indium containing alloys. However consistent pick up has been a problem under normal operating conditions. Solutions to this problem have included Solution TMI™,1 and dual reverse flow bubblers of solid TMI.2 A detailed investigation of the transport characteristics of Solution TMI has been performed, resulting in an increased understanding of its physical properties. This included the use of an Epison III ultrasonic analyzer to monitor the pick up of TMI in the vapor phase at various flow rates (100–1000 sccm), pressures (0.3 and 1 atm.) and temperatures (10–40°C). Solution TMI was shown to have a more consistent ‘pick up’ than dual reverse flow bubblers containing solid TMI. Side by side growth studies of AlInAs and InAlGaAs from Solution TMI and solid adduct grade TMI have shown that Solution TMI also gives layers with reduced oxygen incorporation.