Test structure and test method for evaluating tddb polarity difference of gate oxide layer

Abstract

A t structure and a test method for evaluate a polarity difference of a gate oxide layer TDDB. That test structure comprises a first t transistor. In the first test transistor, a first back gate is respectively connected with a first source stage and a first drain; A first measurement module connected to the first gate; A second test transistor, wherein the second back gate is connected to the second source stage and the second drain, respectively, and the second back gate and the first back gate are connected to each other; A second measurement module connected to the second gate, the secondmeasurement module and the first measurement module being adapted to perform constant current pressurization on the first test transistor and the second test transistor, wherein the first test transistor and the second test transistor are in different polarities in an electrical state when the first test transistor and the second test transistor are under constant current pressurization; A third measurement module connected to the second back gate and the first back gate, respectively. The test structure improves the reliability of evaluating the performance of the gate oxide layer TDDB.

Description

technical field [0001] The invention relates to the field of semiconductor testing, in particular to a testing structure and testing method for evaluating the TDDB polarity difference of a gate oxide layer. Background technique [0002] With the continuous improvement of VLSI integration, the gate oxide layer in MOS transistors is also becoming thinner, but the impact of higher electric field strength on the performance of the gate oxide layer has become a prominent problem. Therefore, the breakdown of the gate oxide layer, such as time dependent dielectric breakdown (TDDB, time dependent dielectric breakdown) of the gate oxide layer has always been a hot issue in the field of VLSI reliability research. [0003] The upper interface and the lower interface of the gate oxide layer are affected by many processes, so that the time-dependent breakdown performance of the gate oxide layer is affected, and the time-dependent breakdown performance of the gate oxide layer is dependent...

AI Technical Summary

Problems solved by technology

[0004] However, in the prior art, usually only the time-dependent breakdown performance of the gate oxide layer in one polarity state can be tested in one test

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