Research On Application Of RRAM And Its Application In FPGA Design

The Field Programmable Logic Gate Array Device (FPGA) is widely used among commercial electronics, communication devices and so on, because of many advantages, such as easily configurable, short time to market and low design cost. The SRAM-based FPGAs are quite popular among commercial portable consumer terminal for high speed and low cost, but it surfs from many more hardware cost for programming circuit. As for anti-fuse and flash based FPGAs are non-volatile but suffer from CMOS process compatibility and high programming voltage. The fourth fundamental electronic device:memristor,or RRAM is a promising device which can be applied in FPGA device to overcome the shortages of SRAM, anti-fuse and flash based FPGA. In this thesis,Two key problems are expounded. First of all, a complicated analysis of the RRAM mathematic model is presented, then a novel RSRAM(Resistor Static Random Access Memory)configuration circuit which can be applied in FPGA is explained.A mathematical model of RRAM is expounded. A complex model is applied to explain the voltage and current characters of RRAM. With the complex impedance, the four fundamental devices,such as resistor, capacitor, inductance and memristor can be expressed in the Ohm’s Law.Then a physics mechanism of memristor is explained. In the complex model of RRAM, the phase can be derived from the barrier of the interface, the margin is derived from the linear migration of holes. A simulation and mathematical verification is done.A novel RSRAM configuration circuit is designed, which combines the High speed advantage of SRAM and the non-volatile advantage of Flash. It consists of RRAM circuit which is composed of two transistors and a memristor and SRAM circuit which is composed of two cross-coupling inverters and two transistors. It can work in two different modes. One is the high speed online-programming SRAM mode, during which the RRAM programming control transistors are all shunt off, while the SRAM cell works independently. Another mode is the non-volatile offline-programming mode. During the non-volatile working mode, the RRAM can be programming at first, then the SRAM cell read the data from the RRAM, at last the SRAM can configurate functional blocks in the FPGA. So the FPGA works. Compared with the traditional SRAM configuration circuit, the novel RSRAM configuration circuit has a bit larger area, However, its non-volatile and3D stacked characters can overcome its area disburse.A RSRAM array is designed to verify the function and performance of the10T2R RSRAM circuit. It consists of thirty-two rows and thirty-two columns RSRAM cells,decoder circuits and read&write driver circuits.Simulation and layout design of the RSRAM array is introduced at last.