The present invention provides for sequential chemical vapor deposition by employing a reactor operated at low pressure, a pump to remove excess reactants, and a line to introduce gas into the reactor through a valve. A first reactant forms a monolayer on the part to be coated, while the second reactant passes through a radical generator which partially decomposes or activates the second reactant into a gaseous radical before it impinges on the monolayer. This second reactant does not necessarily form a monolayer but is available to react with the monolayer. A pump removes the excess second reactant and reaction products completing the process cycle. The process cycle can be repeated to grow the desired thickness of film.

Sequential chemical vapor deposition

Compositional and structural analysis of aluminum oxide films prepared by plasma-enhanced chemical vapor deposition

Review—Investigation and Review of the Thermal, Mechanical, Electrical, Optical, and Structural Properties of Atomic Layer Deposited High-k Dielectrics: Beryllium Oxide, Aluminum Oxide, Hafnium Oxide, and Aluminum Nitride John T. Gaskins,a Patrick E. Hopkins,a,b,c,z Devin R. Merrill,d,e Sage R. Bauers,d Erik Hadland,d David C. Johnson,d,z Donghyi Koh,e,f Jung Hwan Yum,f Sanjay Banerjee,f,∗ Bradley J. Nordell,g Michelle M. Paquette,g Anthony N. Caruso,g William A. Lanford,h Patrick Henry,e Liza Ross,e Han Li,e Liyi Li,e Marc French,e Antonio M. Rudolph,e and Sean W. Kinge,∗,z

https://iopscience.iop.org/article/10.1149/2.0091710jss/pdf

Review—Investigation and Review of the Thermal, Mechanical, Electrical, Optical, and Structural Properties of Atomic Layer Deposited High-k Dielectrics: Beryllium Oxide, Aluminum Oxide, Hafnium Oxide, and Aluminum Nitride

The excellent surface passivation of crystalline silicon provided by Al2O3 requires always an activation by a thermal post-deposition treatment. In this work, we present an indirect study of the reaction kinetics during such thermal activation treatments for Al2O3 synthesized by atomic layer deposition. The study was performed for Al2O3 deposited at varying temperatures, which results in different micro-structures of the films and, in particular, different hydrogen concentrations. The effective carrier lifetime was measured sequentially as a function of the annealing time and temperature. From these data, the reaction rate Ract and the activation energy EA were extracted. The results revealed a rather constant EA in the range of 1.4 to 1.5 eV, independent of the deposition temperature. The reaction rate, however, was found to increase with decreasing deposition temperature, which correlates with an increasing amount of hydrogen being incorporated in the Al2O3 films. This is a strong indication for an inte...

Reaction kinetics during the thermal activation of the silicon surface passivation with atomic layer deposited Al2O3

Self-limiting growth of Al2O3 is accomplished using both pulsed plasma-enhanced (PE) CVD and plasma-enhanced atomic layer deposition (PEALD). In pulsed PECVD the two reactants (Al(CH3)3/TMA and O2) are supplied continuously, while in PEALD the TMA is delivered in pulses separated by purge steps. For both processes the rate per cycle saturates with ∼200 L of TMA exposure. At 165 °C a rate of 1.37 A per cycle is obtained using PEALD. For pulsed PECVD the rate scales linearly with the TMA partial pressure, and its extrapolation is in good agreement with PEALD. The results suggest that deposition in pulsed PECVD involves an ALD component which is supplemented by PECVD growth, and that the contribution of the latter may be tuned using the TMA partial pressure. Experiments using patterned wafers support this hypothesis. Conformal coatings are observed within 10:1 aspect ratio trenches using pulsed PECVD; however the deposition rate on the surface of these substrates is greater than within the trench. The ratio between the two corresponds well to the ratio of rates obtained from pulsed PECVD and PEALD on planar substrates. With cycle times <1 s, net rates up to 20 nm min−1 are obtained by pulsed PECVD while retaining high quality and digital control.

An Analysis of the Deposition Mechanisms involved during Self-Limiting Growth of Aluminum Oxide by Pulsed PECVD†

A plasma deposition technique for amorphous aluminum oxide films is discussed. A 450 kHz or 13.56 MHz power supply was used to generate the plasma and the deposition of the film was achieved at low plasma power using trimethyl-aluminum and carbon dioxide reactant sources. It has been found that for the low frequency plasma the growth is strongly dependent upon TMA concentration, indicating that the growth process is mass transport limited. On the other hand using the 13.56 MHz discharge results in a surface controlled growth rate. An increase in the deposition temperature up to 300° C makes the films more dense and lowers their etching rate. FTIR and ESCA measurements showed that oxidation is only completed with high CO2 concentrations and a deposition temperature above 250° C. The dielectric films were found to have a dielectric constant in the range 7.3=2-9 and a refractive index between 1.5–1.8 depending upon deposition conditions.

A. Talebian

Papers

Plasma deposition of aluminum oxide films