MOS Transistor Failure Detection via Recess Profile Analysis
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Solution Overview
Problem
Current methods for detecting MOS transistor failure, such as through transmission electron microscopy (TEM) analysis, inaccurately determine the position of the lightly doped drain (LDD) region due to etching solution affecting the substrate profile, making it difficult to assess transistor failure accurately.
Innovation Solution
A detection method involving removing contacts to form contact holes, using a controlled wet etching process to create recesses, filling them with a protective material, and analyzing the cross-sectional profiles of these recesses to determine transistor failure accurately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sample is placed in the etching solution to remove the source/drain structure, then the source/drain structure is removed to form a recess, but the etching solution also etches the substrate around the source/drain structure, causing the profile of the formed recess to change and thus cannot accurately correspond to the profile of the source/drain structure
Solution Approach 1:
The patent segments the substrate into two distinct regions: a first region containing the source/drain structure to be etched, and a second region (patterned substrate) that serves as a protective mask. This segmentation allows the etching solution to selectively remove the source/drain structure while the patterned substrate protects the surrounding substrate from etching damage, preserving the accurate profile of the formed recess for detection
Solution Approach 2:
The patterned substrate acts as an intermediary protective layer between the etching solution and the substrate. This intermediary prevents the etching solution from directly contacting and damaging the substrate around the source/drain structure, while still allowing the etching process to proceed on the source/drain structure to form the recess with an accurate profile that corresponds to the original source/drain structure
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables quick and precise determination of MOS transistor failure by ensuring the recess profiles accurately reflect the source/drain structure, minimizing substrate damage and improving detection accuracy.
Implementation Method 1
a method for removing the source and the drain includes performing a wet etching process through the contact holes
Implementation Method 2
obtaining the cross-sectional profile of the recess includes using a transmission electron microscopy to obtain an image of the cross-sectional profile of the recess
Data Source
AI summary
A detection method of a metal-oxide-semiconductor (MOS) transistor is provided. The detection method includes the following steps. A MOS transistor is provided, wherein a source and a drain of the MOS transistor are each connected to a contact. The contacts are removed to form contact holes exposing the source and the drain. The source and the drain are removed through the contact holes to form recesses. The contact holes and the recesses are filled with a protective material. The cross-sectional profiles of the recesses are obtained. It is determined whether the MOS transistor is failed according to the cross-sectional profiles of the recesses.