Programmed Rate Chemical Vapor Deposition Protocols

Abstract

Programmed rate chemical vapor deposition (PRCVD), in which conditions are systematically changed during deposition, studies of tungsten and aluminum are presented. In the tungsten study, PRCVD provided significantly greater throughput than conventional, constant rate CVD (CRCVD). We started the deposition process at a much higher rate then decreased the temperature during deposition. We achieved throughput increases of about a factor of three, with more improvement clearly obtainable. In addition to the increase in throughput, the properties of the PRCVD films were equal to, or superior to, CRCVD films. In the aluminum study, we demonstrated that PRCVD processes can yield films with better properties than CRCVD processes. PRCVD films can have higher nuclei densities, higher fractions of (111) orientated Al, lower surface roughnesses, higher reflectivities, and resistivities closer to that of bulk aluminum. For example, pulsing (starting and stopping) the precursor flow at the start of the temperature ramp down (−200 K/min) from 673 K (for 5 or 10 s), followed by deposition at 573 K yielded better films than similar traditional CRCVD processes. In general, PRCVD protocols provide degrees of freedom that can be used to improve processing or film properties. © 2000 The Electrochemical Society. All rights reserved.