US 6,274,501 B1Granted

Formation of structure to accurately measure source/drain resistance

AssigneeAdvanced Micro Devices, Inc.

InventorsConcetta Riccobene, Ognjen Milic-Strkalj

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Abstract

A method is provided for directly measuring the source/drain resistance of a metal oxide semiconductor (MOS) device. Embodiments include partially deconstructing a typical MOS device by removing its gate and gate oxide from the substrate, as by etching, while preserving its gate sidewall spacer (typically silicon nitride). A sacrificial oxide spacer is formed on the nitride spacer, as by anisotropically etching a deposited oxide layer, and the area surrounding the sacrificial oxide spacer is filled with a layer of nitride. The sacrificial oxide spacer is then selectively etched to expose a portion of the main surface of the substrate and leave the nitride spacer and layer, thus creating a location near the edge of a source/drain region for a metal contact to be formed, as by chemical vapor deposition (CVD). The source/drain resistance of the device can then be directly and accurately measured by making electrical contact to the newly formed contact and a pre-existing source/drain contact on the same active area.

Claims10

Dependent claims

A method for forming an electrical contact on a main surface of a semiconductor substrate to an active region in the substrate, wherein a gate oxide layer is disposed on a portion of the active region and extends over an edge of the active region, a gate is disposed on the gate oxide layer, and a sidewall spacer of a dielectric material is disposed on a sidewall of the gate and extends onto the active region, the method comprising:

etching to remove the gate;
etching to remove the gate oxide layer;
forming a sacrificial oxide layer on the sidewall spacer and the main surface;
anisotropically etching the sacrificial oxide layer to form a sacrificial oxide spacer on the sidewall spacer and extending onto the main surface;
forming a layer of the dielectric material on the sacrificial oxide spacer and extending onto the main surface;
selectively etching to remove the sacrificial oxide spacer and expose a portion of the main surface while preserving the sidewall spacer and dielectric material layer;
and
forming a metal layer on the exposed portion of the main surface between the sidewall spacer and the dielectric material layer to form the electrical contact.

5 more elements

Dependencies are inferred from the claim text.