Effect of W coating on microengine performance

Conference · Wed Mar 01 04:00:00 EST 2000

OSTI ID:752171

MANI, SEETHAMBAL S ^[1]; FLEMING, JAMES G; WALRAVEN, JEREMY A; SNIEGOWSKI, JEFFRY J; DE BOER, MAARTEN P; IRWIN, LLOYD W; TANNER, DANELLE M; LAVAN, DAVID A; DUGGER, MICHAEL T; JAKUBCZAK, II, JEROME F; MILLER, WILLIAM M

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1. Sandia National Laboratories

Two major problems associated with Si-based MEMS (MicroElectroMechanical Systems) devices are stiction and wear. Surface modifications are needed to reduce both adhesion and friction in micromechanical structures to solve these problems. In this paper, the authors present a CVD (Chemical Vapor Deposition) process that selectively coats MEMS devices with tungsten and significantly enhances device durability. Tungsten CVD is used in the integrated-circuit industry, which makes this approach manufacturable. This selective deposition process results in a very conformal coating and can potentially address both stiction and wear problems confronting MEMS processing. The selective deposition of tungsten is accomplished through the silicon reduction of WF{sub 6}. The self-limiting nature of the process ensures consistent process control. The tungsten is deposited after the removal of the sacrificial oxides to minimize stress and process integration problems. The tungsten coating adheres well and is hard and conducting, which enhances performance for numerous devices. Furthermore, since the deposited tungsten infiltrates under adhered silicon parts and the volume of W deposited is less than the amount of Si consumed, it appears to be possible to release adhered parts that are contacted over small areas such as dimples. The wear resistance of tungsten coated parts has been shown to be significantly improved by microengine test structures.

• Research Organization: Sandia National Labs., Albuquerque, NM (US); Sandia National Labs., Livermore, CA (US)
• Sponsoring Organization: US Department of Energy (US)
• DOE Contract Number: AC04-94AL85000
• OSTI ID: 752171
• Report Number(s): SAND2000-0539C
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
CHEMICAL VAPOR DEPOSITION
ENGINES
HYBRID SYSTEMS
MICROELECTRONIC CIRCUITS
MINIATURIZATION
PROTECTIVE COATINGS
TUNGSTEN
WEAR RESISTANCE