Browse Prior Art Database

Particle Detector

IP.com Disclosure Number: IPCOM000047297D
Original Publication Date: 1983-Oct-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 34K

Publishing Venue

IBM

Related People

Harper, JME: AUTHOR [+3]

Abstract

An interdigitated electrode sensor device mounted on a suitable substrate is described below. The electrode material is a conductor. Resistance and capacitance are measured between pairs of electrodes 12 and 14 (Fig. 1). A particle landing on the electrode array 10 is detected, and its electrical properties measured by the change in impedance observed. The impedance can be measured as a function of frequency to determine particle properties (e.g., metal or insulator). The detector is continuously monitored with electrical readout. The device has been demonstrated with Pd electrodes. Desirable electrode properties are resistance to oxidation and inertness to the test environment. Electrodes of line widths and spacings down to 0.5 mm have been tested. A Pd electrode array with 0.

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Particle Detector

An interdigitated electrode sensor device mounted on a suitable substrate is described below. The electrode material is a conductor.

Resistance and capacitance are measured between pairs of electrodes 12 and 14 (Fig. 1). A particle landing on the electrode array 10 is detected, and its electrical properties measured by the change in impedance observed. The impedance can be measured as a function of frequency to determine particle properties (e.g., metal or insulator). The detector is continuously monitored with electrical readout. The device has been demonstrated with Pd electrodes. Desirable electrode properties are resistance to oxidation and inertness to the test environment. Electrodes of line widths and spacings down to 0.5 mm have been tested. A Pd electrode array with
0.5 mm lines and spaces was fabricated on a Si wafer using electron beam lithography. The electrodes were ion-beam deposited through a suitable mask, and the mask removed. Resistance was measured with a Simpson meter over a period of one week in a lab environment.

Results are shown in Fig. 2. At the end of the experiment, particles were blown off with filtered N2 and an expected resistance rise was observed. Fig. 2 represents a plot of resistance vs time of a 0.1 mm x 0.1 mm interdigitated electrode structure in a lab environment. In a further experiment utilizing the above structure, the resistance of the electrode pattern was observed under the following conditions: 1. Det...