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Title: Calorimetric gas sensor

Abstract

A combustible gas sensor is described that uses a resistively heated, noble metal-coated, micromachined polycrystalline Si filament to calorimetrically detect the presence and concentration of combustible gases. The filaments tested to date are 2 {micro}m thick {times} 10{micro}m wide {times} 100, 250, 500, or 1000 {micro}m-long polycrystalline Si; some are overcoated with a 0.25 {micro}m-thick protective CVD Si{sub 3}N{sub 4} layer. A thin catalytic Pt film was deposited by CVD from the precursor Pt(acac){sub 2} onto microfilaments resistively heated to approximately 500 C; Pt deposits only on the hot filament. Using a constant-resistance-mode feedback circuit, Pt-coated filaments operating at ca. 300 C (35 mW input power) respond linearly, in terms of the change in supply current required to maintain constant resistance (temperature), to H{sub 2} concentrations between 100 ppm and 1% in an 80/20 N{sub 2}/O{sub 2} mixture. Other catalytic materials can also be used. 11 figs.

Inventors:
; ; ; ; ; ;
Issue Date:
Research Org.:
Sandia National Laboratories (SNL), Albuquerque, NM, and Livermore, CA (United States)
Sponsoring Org.:
USDOE, Washington, DC (United States)
OSTI Identifier:
675786
Patent Number(s):
5834627
Application Number:
PAN: 8-766,142
Assignee:
Sandia Corp., Albuquerque, NM (United States)
DOE Contract Number:  
AC04-94AL85000
Resource Type:
Patent
Resource Relation:
Other Information: PBD: 10 Nov 1998
Country of Publication:
United States
Language:
English
Subject:
08 HYDROGEN FUEL; CALORIMETERS; GAS ANALYSIS; POLYCRYSTALS; SILICON; PLATINUM; HYDROGEN

Citation Formats

Ricco, A J, Hughes, R C, Smith, J H, Moreno, D J, Manginell, R P, Senturia, S D, and Huber, R J. Calorimetric gas sensor. United States: N. p., 1998. Web.
Ricco, A J, Hughes, R C, Smith, J H, Moreno, D J, Manginell, R P, Senturia, S D, & Huber, R J. Calorimetric gas sensor. United States.
Ricco, A J, Hughes, R C, Smith, J H, Moreno, D J, Manginell, R P, Senturia, S D, and Huber, R J. Tue . "Calorimetric gas sensor". United States.
@article{osti_675786,
title = {Calorimetric gas sensor},
author = {Ricco, A J and Hughes, R C and Smith, J H and Moreno, D J and Manginell, R P and Senturia, S D and Huber, R J},
abstractNote = {A combustible gas sensor is described that uses a resistively heated, noble metal-coated, micromachined polycrystalline Si filament to calorimetrically detect the presence and concentration of combustible gases. The filaments tested to date are 2 {micro}m thick {times} 10{micro}m wide {times} 100, 250, 500, or 1000 {micro}m-long polycrystalline Si; some are overcoated with a 0.25 {micro}m-thick protective CVD Si{sub 3}N{sub 4} layer. A thin catalytic Pt film was deposited by CVD from the precursor Pt(acac){sub 2} onto microfilaments resistively heated to approximately 500 C; Pt deposits only on the hot filament. Using a constant-resistance-mode feedback circuit, Pt-coated filaments operating at ca. 300 C (35 mW input power) respond linearly, in terms of the change in supply current required to maintain constant resistance (temperature), to H{sub 2} concentrations between 100 ppm and 1% in an 80/20 N{sub 2}/O{sub 2} mixture. Other catalytic materials can also be used. 11 figs.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1998},
month = {11}
}