Particle contamination in low pressure organometallic chemical vapor deposition reactors: Methods of particle detection and causes of particle formation using a liquid alane (AlH3) precursor

Abstract

Two methods of analyzing particles were interfaced to a low pressure chemical vapor deposition reactor used to deposit Al films from the liquid precursor dimethylethylamine alane. A laser light scattering particle counter was used to monitor particles (≳200 nm) in real time and established that the appearance of particles corresponded to the flow of precursor into the reactor. A particle impaction system was used to collect particles (≳20 nm) for analysis using analytical transmission electron microscopy and electron diffraction. Typical sizes of the Al particles were in the range 20–1000 nm. Purposely introducing trace amounts of H2O, CO, and O2 into the reactor during the flow of the precursor caused an increase in the number of particles. Our results suggested that Al particle formation was induced by impurities in the gas phase (particularly H2O) although competing mechanisms could not be ruled out.

Laser-Assisted Room-Temperature Film Growth Using a Constrained Pulsed Nozzle Expansion

“…The existence of water as an impurity in the sample handling system is presently still a problem; thus, oxygen as a product must be included as a possibility in any analysis. Such observations have been made previously in analogous systems . Note too that all peaks may also be arising from the fragmentation of higher order species as well as being formed as parent masses.…”

Heavily doped p-type AlGaInP grown by metalorganic chemical vapor deposition

“…The normally used aluminium precursor trimethylaluminium (TMAl) is replaced by dimethyethylamine-alane (DMEAAl). Since the reaction products of DMEAAl with oxygen and water are nonvolatile [6,7], significantly less oxygen will be incorporated in the growing layer compared to layers grown with TMAl. In MOCVD, oxygen contaminations built into the layer through reactions with aluminium form the strong Al-O bond [8].…”

Chemical vapor deposition of Al, Fe and of the Al13Fe4 approximant intermettalic phase

“…A significant delay is observed at low T s (139 o C), where the incubation time equals 310 s. It decreases almost linearly to 48 s at 241 o C where it stabilizes. The observed continuous decrease of the incubation time with increasing the deposition temperature in the low to moderate temperature range, followed by stabilization at high deposition temperature has been reported in the literature for the deposition of Al from DMEAA on Si and SiO 2 substrates (Simmonds et al, 1993). The same behavior has also been observed in the case of the CVD of Si (Kajikawa and Noda, 2005) and Cu (Aviziotis et al, 2013).…”