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Small Device Capacitance Measurement Using a Scanning Electron Microscope

IP.com Disclosure Number: IPCOM000060666D
Original Publication Date: 1986-Apr-01
Included in the Prior Art Database: 2005-Mar-09
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Delecki, JJ: AUTHOR

Abstract

To measure capacitance of devices inaccessible by physical probe connections, e.g. a cell node, features available in a standard electron microscope are utilized. Primary beam electrons are used to charge a cell node. Calibrated energy analysis of secondary electrons allows determination of voltage (V) built up on the cell node as a function of time (t). Substrate current (Isub = current through the cell node to the substrate) is measured. The capacitance C = Isub/(dV/dt) of the cell node is thus determined.

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Small Device Capacitance Measurement Using a Scanning Electron Microscope

To measure capacitance of devices inaccessible by physical probe connections, e.g. a cell node, features available in a standard electron microscope are utilized. Primary beam electrons are used to charge a cell node. Calibrated energy analysis of secondary electrons allows determination of voltage (V) built up on the cell node as a function of time (t). Substrate current (Isub = current through the cell node to the substrate) is measured. The capacitance C = Isub/(dV/dt) of the cell node is thus determined.

Referring to the figure, the primary electron beam 2 of a standard electron microscope is irradiated onto a cell node connection 4 to charge up a diffusion 6 beneath an insulating layer 8. A connection is made to substrate 10 and current to ground is measured by device 12. Secondary electrons 14 reach the collector 16 after passing through energy analyzer 18.

The voltage V on an electrode, e.g. cell node connection 4, is a function of energy Es of the secondary electrons 14 or, V = f(Es). The function, f(Es), is determined by calibration, e.g. applying a series of known potentials to an electrode of material identical to that of node connection 4 and recording resultant secondary electron beam energy Es.

Disclosed anonymously.

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