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一种用于临床监护的无线系统的设计 被引量:1
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作者 吕士龙 马春排 蔡琳华 《电子技术应用》 北大核心 2004年第1期78-80,共3页
介绍了一种基于无线收发模块和单片机的监护系统的设计,阐述了系统的基本原理及硬件的实现。
关键词 无线收发模块 单片机 临床监护 心电监测 PTR2000 数字温度传感器
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小型微纳米图形电子束曝光制作系统(英文) 被引量:2
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作者 殷伯华 方光荣 +3 位作者 刘俊标 靳鹏云 薛虹 吕士龙 《纳米技术与精密工程》 EI CAS CSCD 2010年第4期290-294,共5页
为了满足科学实验过程中对制作半导体器件和微纳米结构的需要,同时避免受到昂贵的工业级电子束曝光(electron beam lithography,EBL)机的条件制约,构建了一种基于普通扫描电子显微镜(scanning electron microsco-py,SEM)的桌面级小型电... 为了满足科学实验过程中对制作半导体器件和微纳米结构的需要,同时避免受到昂贵的工业级电子束曝光(electron beam lithography,EBL)机的条件制约,构建了一种基于普通扫描电子显微镜(scanning electron microsco-py,SEM)的桌面级小型电子束曝光系统.建立了以浮点DSP为控制核心的高速图形发生器硬件系统.利用线性计算方法实现了电子束曝光场的增益、旋转和位移的校正算法.在本曝光系统中应用了新型压电陶瓷电机驱动的精密位移台来实现纳米级定位.利用此位移台所具有的纳米定位能力,采用标记追逐法实现了电子束曝光场尺寸和形状的校准.电子束曝光实验结果表明,场拼接及套刻精度误差小于100 nm.为了测试曝光分辨率,在PMMA抗蚀剂上完成了宽度为30 nm的密集线条曝光实验.利用此系统,在负胶SU8和双层PMMA胶表面进行了曝光实验;并通过电子束拼接和套刻工艺实现了氮化物相变存储器微电极的电子束曝光工艺. 展开更多
关键词 扫描电子显微镜(SEM) 电子束曝光(EBL) 图形发生器 纳米结构
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相变存储器曝光工艺研究
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作者 吕士龙 宋志棠 封松林 《微纳电子技术》 CAS 2006年第6期298-300,共3页
介绍了在相变材料上的曝光工艺研究,得出了相应的工艺条件,研究了邻近效应的影响以及利用邻近效应制作nm量级间隔大电极对的方法。
关键词 曝光 相变材料 邻近效应 电极
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High Speed and Ultra-Low-Power Phase Change Line Cell Memory Based on SiSb Thin Films with Nanoscale Gap of Electrodes Less Than 100 nm
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作者 吕士龙 宋志棠 +1 位作者 张挺 封松林 《Chinese Physics Letters》 SCIE CAS CSCD 2008年第11期4174-4176,共3页
Si16Sbs4-based line cell phase change random access memory (PCRAM), in which the Si16Sbs4 phase change line is contacted by TiN electrodes with a nanoscale gap, is fabricated by electron beam lithography. The lowest... Si16Sbs4-based line cell phase change random access memory (PCRAM), in which the Si16Sbs4 phase change line is contacted by TiN electrodes with a nanoscale gap, is fabricated by electron beam lithography. The lowest current and measured pulse width for RESET operation are 115 μA and 18 ns, respectively. The measured shortest pulse width for recrystallization is 110ns, with applied pulse amplitude of 1.5 V. SET and RESET currents for line cells with different line lengths are determined. Endurance of 106 cycles with a resistance ratio of above 800 has been achieved. 展开更多
关键词 the power-law exponents PRECIPITATION durative abrupt precipitation change
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Nanoscale Tapered Pt Bottom Electrode Fabricated by FIB for Low Power and Highly Stable Operations of Phase Change Memory
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作者 吕士龙 宋志棠 +1 位作者 刘燕 封松林 《Chinese Physics Letters》 SCIE CAS CSCD 2010年第2期295-298,共4页
Phase change random access memory (PC-RAM) based on Si2Sb2Te5 with a Pt tapered heating electrode (Pt-THE), which is fabricated using a focus ion beam (FIB), is investigated. Compared with the tungsten electrode... Phase change random access memory (PC-RAM) based on Si2Sb2Te5 with a Pt tapered heating electrode (Pt-THE), which is fabricated using a focus ion beam (FIB), is investigated. Compared with the tungsten electrode, the Pt-THE facilitates the temperature rise in phase change material, which causes the decrease of reset voltage from 3.6 to 2.7 V. The programming region of the cell with the Pt-THE is smaller than that of the cell with a cylindrical tungsten heating electrode. The improved performance of the PC-RAM with a Pt-THE is attributed to the higher resistivity and lower thermal conductivity of the Pt electrode, and the reduction of the programming region, which is also verified by thermal simulation. 展开更多
关键词 Condensed matter: electrical magnetic and optical Electronics and devices Semiconductors Nanoscale science and low-D systems
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Scaling properties of phase-change line memory
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作者 杜小锋 宋三年 +5 位作者 宋志棠 刘卫丽 吕士龙 顾怡峰 薛维佳 席韡 《Chinese Physics B》 SCIE EI CAS CSCD 2012年第9期554-558,共5页
Phase-change line memory cells with different line widths are fabricated using focused-ion-beam deposited C-Pt as a hard mask. The electrical performance of these memory devices was characterized. The current^oltage ... Phase-change line memory cells with different line widths are fabricated using focused-ion-beam deposited C-Pt as a hard mask. The electrical performance of these memory devices was characterized. The current^oltage (I-V) and resistance-voltage (RV) characteristics demonstrate that the power consumption decreases with the width of the phase-change line. A three-dimensional simulation is carried out to further study the scaling properties of the phase- change line memory. The results show that the resistive amorphous (RESET) power consumption is proportional to the cross-sectional area of the phase-change line, but increases as the line length decreases. 展开更多
关键词 phase-change memory line structure scaling properties three-dimensional simulation
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Set Programming Method and Performance Improvement of Phase Change Random Access Memory Arrays
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作者 范茜 陈后鹏 +6 位作者 王倩 王月青 吕士龙 刘燕 宋志棠 冯高明 刘波 《Chinese Physics Letters》 SCIE CAS CSCD 2015年第6期184-187,共4页
A novel slow-down set waveform is proposed to improve the set performance and a 1 kb phase change random access memory chip fabricated with a 13nm CMOS technology is implemented to investigate the set performance by d... A novel slow-down set waveform is proposed to improve the set performance and a 1 kb phase change random access memory chip fabricated with a 13nm CMOS technology is implemented to investigate the set performance by different set programming strategies based on this new set pulse. The amplitude difference (I1 - I2) of the set pulse is proved to be a crucial parameter for set programming. We observe and analyze the cell characteristics with different I1 - I2 by means of thermal simulations and high-resolution transmission electron microscopy, which reveal that an incomplete set programming will occur when the proposed slow-down pulse is set with an improperly high I1 - I2. This will lead to an amorphous residue in the active region. We also discuss the programming method to avoid the set performance degradations. 展开更多
关键词 PCRAM Set Programming Method and Performance Improvement of Phase Change Random Access Memory Arrays
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The effect of oxygen plasma ashing on the resistance of TiN bottom electrode for phase change memory
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作者 高丹 刘波 +10 位作者 李莹 宋志棠 任万春 李俊焘 许震 吕士龙 朱南飞 任佳栋 詹奕鹏 吴汉明 封松林 《Journal of Semiconductors》 EI CAS CSCD 2015年第5期181-186,共6页
Phase change memory (PCM) has been regarded as a promising candidate for the next generation of nonvolatile memory. To decrease the power required to reset the PCM cell, titanium nitride (TIN) is preferred to be u... Phase change memory (PCM) has been regarded as a promising candidate for the next generation of nonvolatile memory. To decrease the power required to reset the PCM cell, titanium nitride (TIN) is preferred to be used as the bottom electrode of PCM due to its low thermal and suitable electrical conductivity. However, during the manufacture of PCM cell in 40 nm process node, abnormally high and discrete distribution of the resistance of TiN bottom electrode was found, which might be induced by the surface oxidation of TiN bottom electrode during the photoresist ashing process by oxygen plasma. In this work, we have studied the oxidation of TiN and found that with the increasing oxygen plasma ashing time, the thickness of the TiO2 layer became thicker and the state of the TiO2 layer changed from amorphous to crystalline, respectively. The resistance of TiN electrode contact chain with 4-5 nm TiO2 layer was confirmed to be almost three-orders of magnitude higher than that of pure TiN electrode, which led to the failure issue of PCM cell. We efficiently removed the oxidation TiO2 layer by a chemical mechanical polishing (CMP) process, and we eventually recovered the resistance of TiN bottom electrode from 1×10^5Ω/via back to 6×10^2 Ωvia and successfully achieved a uniform resistance distribution of the TiN bottom electrode. 展开更多
关键词 PCM oxygen plasma ashing titanium nitride bottom electrode OXIDATION CMP
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