机载激光雷达风切变探测性能分析

介绍了用于风切变测量的激光雷达外差探测系统，阐述了其工作原理，根据CO2雷达系统与Ho：YAG雷达系统相关参数进行信噪比模拟和风速误差对比，模拟结果表明波长为2．1μm的Ho：YAG雷达和波长为10．6μm CO2雷达都适合机载低空风切变探测。通过对比表明Ho：YAG雷达的性能更为优良，误差更小，探测距离更远。     

Enhanced Performance of Phase Change Memory Cell Element by Initial Operation and Non-Cumulative Programming

A phase change memory （PCM） device, based on the Ge2Sb2Te5 （GST） material, is fabricated using the standard 0.18-μm CMOS technology. After serials of detailed experiments on the phase transition behaviors, we find that the RESET process is strongly dependent on the state of the inactive area and the active area affects the SET process dramatically. By applying a 5-mA current-voltage （I — V） sweep as initial operation, we can reduce the voltage drop beyond the active area during the RESET process and the overall RESET voltage decreases from 3 V plus to 2.5 V. For the SET operation, a non-cumulative programming method is introduced to eliminate the impact of randomly formed amorphous active area, which is strongly related to the threshold switching process and SET voltage. Combining the two methods, the endurance performance of the PCM device has been remarkably improved beyond 1 × 106 cycles.     

Switching Characteristics of Phase Change Memory Cell Integrated with Metal-Oxide Semiconductor Field Effect Transistor

A Ge2Sb2Te5 based phase change memory device cell integrated with metal-oxide semiconductor field effect transistor （MOSFET） is fabricated using standard 0.18 #m complementary metM-oxide semiconductor process technology. It shows steady switching characteristics in the dc current-voltage measurement. The phase changing phenomenon from crystalline state to amorphous state with a voltage pulse altitude of 2.0 V and pulse width of 50ns is also obtained. These results show the feasibility of integrating phase change memory cell with MOSFET.     

A 0.18-μm 3.3 V 16 k Bits 1RIT Phase Change Random Access Memory （PCRAM） Chip

Using standard 0.18-μm CMOS process and the special platform for S-inch phase change random access memory （PCRAM）, the first Chinese 16k bits PCRAM chip has been successfully achieved. A 1RIT structure has been designed for low voltage drop and low cost compared to the 1RlD structure and the BJT-switch structure. Full integration of the 16k bits PCRAM chip, including memory cell, array structure, critical circuit module, and physical layout, has been designed and verified. The critical integration technology of the phase change material （PCM） fabrication and the standard CMOS process has been solved. Test results about PCM in a large-scale array have been generated for the next research of PCRAM chip.