Dynamic random access memory device and inspection method thereof
AssigneeElpida Memory, Inc.
InventorsYuki MORI, Kensuke OKONOGI, Shuichi TSUKADA
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Abstract
A memory cell potentially including a retention fault attributable to a random change over time of data retention capability is screened by applying a bias to a gate electrode such that holes are accumulated on an interface of a substrate that is a component of a memory cell transistor on the side of the gate electrode and, after applying the bias, performing a pause-refresh test for inspecting the data retention capability of the memory cell.
Claims6
An inspection method of a dynamic random access memory device mounted with a plurality of memory cells having data retention capabilities,
- the memory cells including a substrate, a source-drain region provided in a vicinity of a surface of the substrate, and a gate formed by laminating a gate insulator film provided on the surface of the substrate so as to cover an end of the source-drain region and a gate electrode, the inspection method comprising:
- applying a bias to the gate electrode so that a hole is accumulated on an interface on the side of the gate electrode in a vicinity of an interface between the gate and the substrate and in a region where the gate and the substrate face each other, and performing a pause-refresh test for inspecting the data retention capability after applying the bias;
- and
- screening a memory cell potentially including a retention fault attributable to a random change over time of the data retention capability from among the plurality of memory cells.
A dynamic random access memory device mounted with a plurality of memory cells having data retention capabilities, the dynamic random access memory device comprising
- an inspecting section that executes an inspection of the dynamic random access memory device, wherein
- the memory cells include a substrate, a source-drain region provided in a vicinity of a surface of the substrate, and a gate formed by laminating a gate insulator film provided on the surface of the substrate so as to cover an end of the source-drain region and a gate electrode, and
- the inspecting section includes:
- a test circuit for applying, to the gate electrode, a bias such that a hole is accumulated on an interface on the side of the gate electrode in a vicinity of an interface between the gate and the substrate and in a region where the gate and the substrate face each other;
- a pause-refresh test circuit for inspecting the data retention capability, and
- a switching circuit that switches between the test circuit and the pause-refresh test circuit.
Dependencies are inferred from the claim text.