本文采用快速液相烧结法制备了Gd2O3掺杂BiFeO3陶瓷, 并对陶瓷样品进行了物相、形貌、漏电流特性和磁性能研究。XRD分析结果表明, Gd2O3的加入促进了富铋相(Bi25FeO40)的形成且使晶胞体积减小, 同时陶瓷的物相由三方相向正交相转变; SEM分析结果表明, Gd2O3掺杂能起到细化陶瓷晶粒的作用; 电学性能分析表明, 陶瓷样品漏电流较大, 但Gd2O3的掺杂可显著降低陶瓷的漏电流; 漏电流特性分析结果表明, 陶瓷在低电场下的漏电流特性是欧姆传导机制, 在高电场下纯BiFeO3陶瓷的漏电流特性为肖特基发射机制, 但随着Gd2O3掺杂量的增加而逐渐变为空间电荷限制电流传导(SCLC)机制; 磁性研究结果表明, 掺杂引入的磁性Gd2O3颗粒均匀分布在陶瓷的晶界处从而显著提高陶瓷磁性能。

Most widely used dielectrics for MLCC are based on BaTiO₃ composition which inevitably shows performance degradation during the application due to the migration of oxygen vacancies (Vo⋅⋅). Here, the BaTiO₃, (Ba0.97Ca0.03)TiO₃, Ba(Ti0.98Mg0.02)O₃, (Ba0.97Ca0.03)(Ti0.98Mg0.02)O₃, (Ba0.96Ca0.03Dy0.01)(Ti0.98Mg0.02)O₃ ceramics (denoted as BT, BCT, BTM, BCTM and BCDTM, respectively) were prepared by a solid-state reaction method. The core-shell structured grains (∼200 nm) featured with 10-20 nm wide shell were observed and contributed to the relatively flat dielectric constant-temperature spectra of BTM, BCTM and BCDTM ceramics. The TSDC study found that the single/ mix doping of Ca2+, especially the Mg2+, Mg2+/Ca2+ and Mg2+/Ca2+/Dy3+ could limit the emergence of Vo⋅⋅ during the sintering and suppress its long-range migration under the electric-field. Because of this, the highly accelerated lifetimes of the ceramics were increased and the value of BCDTM is 377 times higher than that of BT ceramics. The p−n junction model was built to explain the correlation mechanism between the long-range migration of Vo⋅⋅ and the significantly increased leakage current of BT-based dielectrics in the late stage of HALT.

采用溶胶-凝胶法在Pt/Ti/SiO2/Si衬底上成功制备了BiFe1-xZnxO3(BFZO)(x=0、2%、4%、6%)(摩尔分数)薄膜, 并系统研究了Zn掺杂对BiFeO3(BFO)薄膜结构、表面形貌、漏电流密度、铁电及铁磁性能的影响。XRD图谱显示, 所有样品均为钙钛矿结构, 无其他杂质相引入。扫描电子显微镜(SEM)测试表明, 当Zn掺杂量(x)为4%时, BFZO薄膜表现出均匀的细晶粒和更高的密度, 有助于改善漏电流密度。漏电流密度曲线表明, 在300 kV/cm的电场下, BiFe0.96Zn0.04O3薄膜的漏电流密度(J)最低为1.56×10-6 A/cm2, 比纯BFO薄膜的低3个数量级。同时, BiFe0.96Zn0.04O3薄膜在室温下表现出较大的剩余极化(2Pr=20.91 μC/cm2), 是BFO(2Pr=4.96 μC/cm2)的4倍多。此外, Zn掺杂也增强了BFO薄膜的铁磁性能, 随着Zn掺杂浓度的提高, BFZO薄膜的饱和磁化强度显著增强, 使BiFeO3薄膜在信息存储方面存在潜在的应用价值。

提出了一种用于降低触发电压的两级防护SCR(TSPSCR)。在传统LVTSCR中植入P-ESD层, 增设额外的二极管。因为P-ESD层的掺杂浓度较高, 该器件能更早发生雪崩击穿而触发第一级泄流路径, 从而开启第二级泄流路径。Sentaurus TCAD仿真结果表明, 该器件的触发电压从传统器件的10.59 V降低至4.12 V, 维持电压为1.25 V, 1 V直流电压下漏电流仅为7.85 nA。优化后的TSPSCR适用于先进1 V工作电压的电路中。

提出了一种新型隐埋缓冲掺杂层(IBBD)高压SBD器件, 对其工作特性进行了理论分析和模拟仿真验证。与常规高压SBD相比, 该IBBD-SBD在衬底上方引入隐埋缓冲掺杂层, 将反向击穿点从常规结构的PN结保护环区域转移到肖特基势垒区域, 提升了反向静电释放(ESD)能力和抗反向浪涌能力, 提高了器件的可靠性。与现有表面缓冲掺杂层(ISBD)高压SBD相比, 该IBBD-SBD重新优化了漂移区的纵向电场分布形状, 在保持反向击穿点发生在肖特基势垒区域的前提下, 进一步降低反向漏电流、减小正向导通压降, 从而降低了器件功耗。仿真结果表明, 新器件的击穿电压为118 V。反向偏置电压为60 V时, 与ISBD-SBD相比, 该IBBD-SBD的漏电流降低了52.2%, 正向导通电压更低。

对不同几何尺寸的8型栅NMOS,在受到总剂量辐射影响时其电参数特性的损伤或退化特性,以及与常规结构抗总剂量能力或参数损伤变化比较的异同进行了研究。研究结果表明,栅源重叠宽度和宽长比对8型栅关态漏电流的影响相比直栅可以忽略不计; 任一几何尺寸8型栅NMOS饱和漏极电流在不同辐射总剂量下相比直栅有着良好的稳定性。同时,小宽长比8型栅饱和漏极电流的差异来源于栅源重叠宽度的不同,大宽长比8型栅饱和漏极电流的大小不再受到栅源重叠宽度的影响; 180 nm工艺下不同几何尺寸8型的栅阈值电压在测试中都稳定在0.41 V,显著优于直栅。

BiFeO₃ thin films were prepared using the chemical solution route on Pt/TiO₂/SiO₂/Si(100) substrates under different crystallization kinetics. The crystallization kinetic effects on the dielectric and electrical properties have been investigated. These properties included dielectric permittivity, electric modulus, electrical conductivity measurements as a function of the temperature (300–525 K) and frequency (10²–10⁶ Hz), and leakage current measurements electric field range ± 30 kV/cm at room temperature. The differences observed in conductivity and current density of the BiFeO₃ films were discussed in terms of possible defects induced by the crystallization kinetic. An anomalous relaxor-like dielectric behavior characterized by a broad maximum in the real dielectric permittivity as a function of temperature and the low-frequency dielectric dispersion has been observed. The nonexpected peaks in the real permittivity were accompanied by increasing at least four orders in the conductivity’s magnitude at high temperatures. The origin of the relaxor-like dielectric anomalies is discussed, suggesting that the dielectric permittivity peaks are artifacts due to carrier migration correlated to the onset of the Maxwell–Wagner effect.BiFeO₃ thin films were prepared using the chemical solution route on Pt/TiO₂/SiO₂/Si(100) substrates under different crystallization kinetics. The crystallization kinetic effects on the dielectric and electrical properties have been investigated. These properties included dielectric permittivity, electric modulus, electrical conductivity measurements as a function of the temperature (300–525 K) and frequency (10²–10⁶ Hz), and leakage current measurements electric field range ± 30 kV/cm at room temperature. The differences observed in conductivity and current density of the BiFeO₃ films were discussed in terms of possible defects induced by the crystallization kinetic. An anomalous relaxor-like dielectric behavior characterized by a broad maximum in the real dielectric permittivity as a function of temperature and the low-frequency dielectric dispersion has been observed. The nonexpected peaks in the real permittivity were accompanied by increasing at least four orders in the conductivity’s magnitude at high temperatures. The origin of the relaxor-like dielectric anomalies is discussed, suggesting that the dielectric permittivity peaks are artifacts due to carrier migration correlated to the onset of the Maxwell–Wagner effect.

提出了一种新型电源箝位电路, 旨在解决传统电路中存在的泄漏电流大、误触发、低导通时间等问题。该电路通过引入双极晶体管(BJT), 利用BJT电流放大作用以降低电容容值, 再利用MOS管和串联二极管的反馈作用以调整触发电压, 来提升箝位电路的性能。仿真结果表明, 该电路可以快速响应ESD事件, 并且可以实现快速关断的功能, 从而快速泄放电流, 避免对内部电路造成损坏。

碲锰镉(CdMnTe)作为性能优异的室温核辐射探测器材料, 可用于环境监测和工业无损检测领域。本文中采用Te溶剂Bridgman法生长In掺杂Cd0.9Mn0.1Te晶体, 制备成10 mm×10 mm×2 mm大小的室温单平面探测器, 研究了该探测器对241Am@59.5 keV γ射线源的能谱响应。通过表征红外透过率、电阻率以及探测器能谱响应等参数, 综合评定了探测器用CdMnTe晶体的质量、电学和探测器性能。结果表明, 晶片的红外透过率均在55%以上, 最好可达到60%。采用湿法钝化, 100 V偏压下的漏电流由钝化前的9.48 nA降为钝化后的7.90 nA, 钝化后的电阻率为2.832×1010 Ω·cm。在-400 V反向偏压下, CdMnTe探测器对241Am@59.5 keV γ射线源的能量分辨率在钝化前后分别为13.53%和12.51%, 钝化后的电子迁移率寿命积为1.049×10-3 cm2/V。研究了探测器的能量分辨率随电压的变化特性, 当偏压≤400 V时, 探测器的能量分辨率主要由载流子的收集效率决定, 而当偏压>400 V时, 能量分辨率由漏电流决定。本文研究结果表明, Te溶剂Bridgman法生长的CdMnTe晶体质量较好, 电阻率和电子迁移率寿命积满足探测器制备需求。