Test circuit used for measuring SRAM array capacitor and method for measuring SRAM array capacitance

Abstract

The invention provides a test circuit used for measuring SRAM array capacitance and a method for measuring the SRAM array capacitance. The test circuit comprises a to-be-measured SRAM array, a comparative SRAM array compared with the to-be-measured SRAM array, a first PMOS transistor, a first NMOS transistor, a second PMOS transistor and a second NMOS transistor, wherein the first PMOS transistor and the first NMOS transistor correspond to the to-be-measured SRAM array; and the second PMOS transistor and the second NMOS transistor correspond to the comparative SRAM array. According to the test circuit used for measuring the SRAM array capacitance, provided by the invention, a plurality of devices are added in only a test structure, so that the test circuit is simple in structure and easy to realize; and through the test circuit, the capacitance can be indirectly measured by measuring a current rather than directly measuring the capacitance, so that the measurement speed is higher and the measurement precision is higher.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a test circuit for measuring static random access memory (SRAM) array capacitance and a method for measuring SRAM array capacitance. Background technique [0002] For the SRAM array capacitance, the current bridge method is commonly used to measure the capacitance. figure 1 It is the circuit diagram of the bridge method commonly used to measure capacitance at present. Such as figure 1 As shown, the bridge can be balanced by the equation R X +1 / jωC X = R 4 / R 3 (R 2 +1 / jωC 2 ) to represent, then C X = R 3 C 2 / R 4 . The currently commonly used test structure for SRAM array capacitance usually uses an LCR tester (such as Agilent4284) to directly measure the capacitance. The precision of this type of conventional tester is not high, so the error when directly using this type of tester to measure capacitance will be relatively large. Moreover, when the capacitanc...

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Problems solved by technology

The accuracy of this type of conventional tester is not high, so the error when directly using this type of tester to measure capacitance will be relatively large

Moreover, when using an LCR tester to measure capacitance, each test requires capacitance calibration (calibration), which is troublesome

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