A Si-micromachined 48-stage Knudsen pump for on-chip vacuum
This paper describes a thermal transpiration-driven multistage Knudsen pump for vacuum pumping applications. This type of pump relies upon the motion of gas molecules from the cold end to the hot end of a channel in which the flow is restricted to the free molecular or transitional regimes. To achie...
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Published in | Journal of micromechanics and microengineering Vol. 22; no. 10; pp. 105026 - 8 |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
Bristol
IOP Publishing
01.10.2012
Institute of Physics |
Subjects | |
Online Access | Get full text |
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Summary: | This paper describes a thermal transpiration-driven multistage Knudsen pump for vacuum pumping applications. This type of pump relies upon the motion of gas molecules from the cold end to the hot end of a channel in which the flow is restricted to the free molecular or transitional regimes. To achieve a high compression ratio, 48 stages are cascaded in series in a single chip. A five-mask, single silicon wafer process is used for monolithic integration of the designed Knudsen pump. The pump has several monolithically integrated Pirani gauges to experimentally measure the vacuum pumping characteristics of the pump. It has a footprint of 10.35 × 11.45 mm2. For an input power of 1350 mW, the fabricated pump self-evacuates the encapsulated cavities from 760 to 50 Torr, resulting in a compression ratio of 15. It also pumps down from 250 to 5 Torr, resulting in a compression ratio of 50. Each integrated Pirani gauge requires 3.9 mW of power consumption, and its response is sufficiently sensitive in the operating pressure range of 760-1 Torr. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0960-1317 1361-6439 |
DOI: | 10.1088/0960-1317/22/10/105026 |