DFT-Enhanced Test Scheme for Spin-Transfer-Torque (STT) MRAMs

Spin-transfer-torque magnetoresistive random access memory (STT-MRAM) is one promising nonvolatile memory. In this paper, a design-for-testability (DFT)-enhanced test scheme is proposed to enhance the test quality of STT-MRAMs by adaptively adjusting the read current of the read test operations using a read current-adjustable DFT (RCA-DFT) circuit. A march test, March-MT, is proposed as well. Together with RCA-DFT, March-MT requires
$11N$
test complexity to achieve about 7.26 times of total test quality improvement in comparison with a March-6N test algorithm with fixed read current for a STT-MRAM with
$N$
words.