Research On The Testing Technology For The Testing Chip Of Phase Change Random Access Memory

Phase-change random access memory is one of the fastest growing non-volatilememories, and it is different from the traditional memories. The amorphous phase andcrystalline phase of phase change memory cell are used respectively to represent data0and1with the vast difference in resistance of the two states. It needs impulse voltage orcurrent to change state. This brings new challenges to the existing testing methods andtesting technology. This paper, according to the characteristics of phase change memory,proposes testing methods of phase change memory and a solution to testing system toimplement these methods.The main electrical parameters of phase change memory are the resistivity incrystalline and amorphous state, the threshold voltage and current, impulse voltage orcurrent of set and reset operations and write/erase/read operational functions and so on.This paper presents the test methods of the above parameters. And provides a way to testthe peripheral circuits and chip function. The test system is made up of control circuits,testing excitation, parameter testing and interface module. The use of graphicalprogramming language LabView enhances the operability and flexibility of the system. Theintroduction of analog switch, the parasitic energy storage unit of the transmission lines, aswell as the way of time delay by controlling the length of lines, ensures high accuracy ofthe output pulse signal. Meanwhile, a mixed signal interface test board based on dichotomyis designed. The finished test system contains16bit data bus and16bit address bus, cangenerate pulse in width of1ns~1us. And the system contains voltage、current and resistancetest function, and the system has meted the design requirements.The test methods and the testing system, make the test of phase change memorycheaper and easier. It will also advance greatly the study of phase change memory, and atthe same time will provide a reference for test methods and equipments in theindustrialization of phase change memory chip.