Title:
GAS FLOWMETER AND ITS MANUFACTURING METHOD
Document Type and Number:
Japanese Patent JP3698679
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To provide a gas flowmeter which can reduce change with time, and to provide its manufacturing method.
SOLUTION: The gas flowmeter is provided with a silicon semiconductor substrate 2 in which a cavity 9 is formed, and a heat generating resistor 4 formed on the cavity 9 of the substrate 2 via an insulating film 8a. The heat generating resistor 4 is a silicon (Si) semiconductor thin film which is subjected to high density impurity doping. On an upper layer and a lower layer of the semiconductor thin film, a silicon nitride (Si3N4) thin film is formed which is a barrier layer and stoichiometrically stable. Hydrogen is hard to permeate the barrier layer and to be absorbed by the barrier layer, in a heating temperature range of the heating resistor.
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Inventors:
Masamichi Yamada
Junichi Horie
Izumi Watanabe
Keiichi Nakata
Junichi Horie
Izumi Watanabe
Keiichi Nakata
Application Number:
JP2002087727A
Publication Date:
September 21, 2005
Filing Date:
March 27, 2002
Export Citation:
Assignee:
株式会社日立製作所
株式会社日立カーエンジニアリング
株式会社日立カーエンジニアリング
International Classes:
F02D35/00; G01F1/684; G01F1/692; (IPC1-7): G01F1/692
Domestic Patent References:
| JP2002071416A | ||||
| JP2001168281A | ||||
| JP2000111379A | ||||
| JP2002005763A |
Attorney, Agent or Firm:
Kasuga Toshiaki
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