Test Method Of Phase Change Memory Arrays And Simulation Study On HSPICE Model Of Array Thermal Crosstalk

As one of the promising non-volatile solid storage technologies, PCM(Phase change memory) has developed rapidly in recent years because it has many advantages such as fast speed, low power consumption, and can be used to multilevel storage. The core principle of PCM is using the phase change caused by the heat and temperature variations of phase change materials to achieve different memory states. So it is one of the keys to research the temperature characteristics of the phase change storage arrays. The integration of the PCM is restricted by the array fabrication process, capacity and the thermal crosstalk between the memory cells. For large capacity PCM, we need to test the PCM array to give feedback to the fabrication process. As there is no mature methods to test array thermal crosstalk right now, establishing models for further simulation analysis of array thermal crosstalk has great significance to improve PCM integration.For testing the PCM array, this dissertation constructs a test system which can quickly and accurately select the specific cell to test. The core of the system is the cell selection test board, which mainly focuses on the cell selection test board's design and production, containing a line selection circuit and a column selection circuit. Both of the two circuits can realize the gating of multiplexed analog channel by multistage on-off arrays. Then, a PCM array sample was tested with the cell selection test board and the results verified the excellent gating function of the test board and the good property of the PCM array.In order to further analyze the thermal crosstalk phenomenon between the PCM array storage cells, another focus of this dissertation is to establish a PCM array HSPICE model according to the basic principle of electrical, thermal physics and crystal dynamics. In this dissertation, the concept and principle of each module of the model are introduced in detail, and the parameters of each model are determined. First, comparison between the simulation results and the PCM work process can verify the feasibility of the model. Then based on this model, the thermal crosstalk between adjacent cells is simulated. The results showed the relationships between the thermal crosstalk temperature rise, the adjacent cell threshold voltage and the amplitude and the width of the operation pulse. The idea of estimating the temperature rise of the thermal crosstalk and the method of reducing the influence of the thermal crosstalk by the feedback regulation mechanism are put forward in the dissertation.