Inhibiting the bipolar effect via band gap engineering to improve the thermoelectric performance in n-type Bi_(2-x)Sb_(x)Te_(3)for solid-state refrigeration

To date,the benchmark Bi_(2)Te_(3)-based alloys are still the only commercial material system used for ther-moelectric solid-state refrigeration.Nonetheless,the conspicuous performance imbalance between the p-type Bi_(2-x)Sb_(x)Te_(3)and n-type Bi_(2)Te_(3-x)Se_(x) legs has become a major obstacle for the improvement of cooling devices to achieve higher efficiency.In our previous study,novel n-type Bi_(2-x)Sb_(x)Te_(3)alloy has been pro-posed via manipulating donor-like effect as an alternative to mainstream n-type Bi_(2)Te_(3-x)Se_(x).However,the narrow bandgap of Bi_(2-x)Sb_(x)Te_(3)provoked severe bipolar effect that constrained the further improvement of zT near room temperature.Herein,we have implemented band gap engineering in n-type Bi_(1.5)Sb_(0.5)Te_(3)by employing isovalent Se substitution to inhibit the undesired intrinsic excitation and achieve the dis-tinguished room-temperature zT.First,the preferential occupancy of Se at Te^(2)site appropriately enlarges the band gap,thereby concurrently improving the Seebeck coefficient and depressing the bipolar thermal conductivity.In addition,the Se alloying mildly suppresses the compensation mechanism and essentially preserves the already optimized carrier concentration,which maintains the peak zT near room tempera-ture.Moreover,the large strain field and mass fluctuation generated by Se alloying leads to the remark-able reduction of lattice thermal conductivity.Accordingly,the zT value of Bi_(1.5)Sb_(0.5)Te_(2.8)Se_(0.2)reaches 1.0 at 300 K and peaks 1.1 at 360 K,which surpasses that of most well-known room-temperature n-type thermoelectric materials.These results pave the way for n-type Bi_(2-x)Sb_(x)Te_(3)alloys to become a new and promising top candidate for large-scale solid-state cooling applications.

New insight into the parasitic bipolar amplification effect in single event transient production

In this paper, a new method is proposed to study the mechanism of charge collection in single event transient （SET） production in 90 nm bulk complementary metal oxide semiconductor （CMOS） technology. We find that different from the case in the pMOSFET, the parasitic bipolar amplification effect （bipolar effect） in the balanced inverter does not exist in the nMOSFET after the ion striking. The influence of the suhstrate process on the bipolar effect is also studied in the pMOSFET. We find that the bipolar effect can be effectively mitigated by a buried deep P＋-well layer and can be removed by a buried SO2 layer.

Enhanced thermoelectric performance in Ga_(x)Co_(4)Sb_(12.3-y)Te_(y) skutterudites via suppressing bipolar effects for commercial application

The n-type filled and doped skutterudites Ga_(x)Co_(4)Sb_(12.3) and Ga_(0.2)Co_(4)Sb_(11.3)Te composites with the welldistributed GaSb nanoinclusions are synthesized through the manipulating of metastable Ga fillers and enrichment of Sb by an in-situ method with a proper annealing procedure.Ga atoms can fill the icosahedron cages of skutterudite at high temperature,but at low temperature,they are driven out from the lattice voids and form the second phase of GaSb at grain boundaries.The presence of GaSb second phases reduces the thermal conductivity effectively.Te doping leads to a significant increase in carrier concentration of Ga_(0.2)Co_(4)Sb_(11.3)Te,thus largely suppresses the bipolar effect of Ga_(x)Co_(4)Sb_(12.3),resulting in a great enhancement in power factor.Moreover,Te doping induces mass and strain fluctuation,which decreases the lattice thermal conductivity further.Consequently,the maximum ZT is increased from 0.56 for Ga_(0.2)Co_(4)Sb_(12.3) at 573 K to 1.48 for Ga_(0.2)Co_(4)Sb_(11.3)Te at 873 K,which is advantageous to improve the thermoelectric conversion efficiency for commercial application.

Experimental characterization of the bipolar effect on P-hit single-event transients in 65 nm twin-well and triple-well CMOS technologies

Single-event charge collection is controlled by drift, diffusion and the bipolar effect. Previous work has established that the bipolar effect is significant in the p-type metal-oxide-semiconductor field-effect transistor(PMOS) in 90 nm technology and above. However, the consequences of the bipolar effect on P-hit single-event transients have still not completely been characterized in 65 nm technology. In this paper, characterization of the consequences of the bipolar effect on P-hit single-event transients is performed by heavy ion experiments in both 65 nm twin-well and triple-well complementary metal-oxide-semiconductor(CMOS) technologies. Two inverter chains with clever layout structures are explored for the characterization. Ge(linear energy transfer(LET) = 37.4 Me V cm^2/mg) and Ti(LET = 22.2 Me V cm^2/mg) particles are also employed. The experimental results show that with Ge(Ti) exposure, the average pulse reduction is 49 ps(45 ps) in triple-well CMOS technology and 42 ps(32 ps) in twin-well CMOS technology when the bipolar effect is efficiently mitigated. This characterization will provide an important reference for radiation hardening integrated circuit design.

Effects of microwave pulse-width damage on a bipolar transistor

This paper presents a theoretical study of the pulse-width effects on the damage process of a typical bipolar transistor caused by high power microwaves（HPMs） through the injection approach.The dependences of the microwave damage power,P,and the absorbed energy,E,required to cause the device failure on the pulse width τ are obtained in the nanosecond region by utilizing the curve fitting method.A comparison of the microwave pulse damage data and the existing dc pulse damage data for the same transistor is carried out.By means of a two-dimensional simulator,ISE-TCAD,the internal damage processes of the device caused by microwave voltage signals and dc pulse voltage signals are analyzed comparatively.The simulation results suggest that the temperature-rising positions of the device induced by the microwaves in the negative and positive half periods are different,while only one hot spot exists under the injection of dc pulses.The results demonstrate that the microwave damage power threshold and the absorbed energy must exceed the dc pulse power threshold and the absorbed energy,respectively.The dc pulse damage data may be useful as a lower bound for microwave pulse damage data.

Substrate bias effects on collector resistance in SiGe heterojunction bipolar transistors on thin film silicon-on-insulator

An analytical expression for the co/lector resistance of a novel vertical SiGe heterojunction bipolar transistor （HBT） on thin film silicon-on-insulator （SOI） is obtained with the substrate bias effects being considered. The resistance is found to decrease slowly and then quickly and to have kinks with the increase of the substrate-collector bias, which is quite different from that of a conventional bulk HBT. The model is consistent with the simulation result and the reported data and is useful to the frequency characteristic design of 0.13 μtm millimeter-wave SiGe SOI BiCMOS devices.

A device model for thin silicon-on-insulator SiGe heterojunction bipolar transistors with saturation effects

In this paper, we describe the saturation effect of a silicon germanium （SiGe） heterojunction bipolar transistor （HBT） fabricated on a thin silicon-on-insulator （SOI） with a step-by-step derivation of the model formulation. The collector injection width, the internal base-collector bias, and the hole density at the base-collector junction interface are analysed by considering the unique features of the internal and the external parts of the collector, as they are different from those of a bulk counterpart.

Early effect modeling of silicon-on-insulator SiGe heterojunction bipolar transistors

Silicon germanium （SiGe） heterojunction bipolar transistor （HBT） on thin silicon-on-insulator （SOI） has recently been demonstrated and integrated into the latest SOI BiCMOS technology. The Early effect of the SOI SiGe HBT is analysed considering vertical and horizontal collector depletion, which is different from that of a bulk counterpart. A new compact formula of the Early voltage is presented and validated by an ISE TCAD simulation. The Early voltage shows a kink with the increase of the reverse base-collector bias. Large differences are observed between SOI devices and their bulk counterparts. The presented Early effect model can be employed for a fast evaluation of the Early voltage and is useful to the design, the simulation and the fabrication of high performance SOI SiCe devices and circuits.

Radiation effects on MOS and bipolar devices by 8 MeV protons,60 MeV Br ions and 1 MeV electrons

The radiation effects of the metal-oxide-semiconductor （MOS） and the bipolar devices are characterised using 8 MeV protons, 60 MeV Br ions and 1 MeV electrons. Key parameters are measured in-situ and compared for the devices. The ionising and nonionising energy losses of incident particles are calculated using the Geant4 and the stopping and range of ions in matter code. The results of the experiment and energy loss calculation for different particles show that different incident particles may give different contributions to MOS and bipolar devices. The irradiation particles, which cause a larger displacement dose within the same chip depth of bipolar devices at a given total dose, would generate more severe damage to the voltage parameters of the bipolar devices. On the contrary, the irradiation particles, which cause larger ionising damage in the gate oxide, would generate more severe damage to MOS devices. In this investigation, we attempt to analyse the sensitivity to radiation damage of the different parameter of the MOS and bipolar devices by comparing the irradiation experimental data and the calculated results using Geant4 and SRIM code.

Experimental verification of the parasitic bipolar amplification effect in PMOS single event transients

The contribution of parasitic bipolar amplification to SETs is experimentally verified using two P-hit target chains in the normal layout and in the special layout. For PMOSs in the normal layout, the single-event charge collection is composed of diffusion, drift, and the parasitic bipolar effect, while for PMOSs in the special layout, the parasitic bipolar junction transistor cannot turn on. Heavy ion experimental results show that PMOSs without parasitic bipolar amplification have a 21.4% decrease in the average SET pulse width and roughly a 40.2% reduction in the SET cross-section.

丙戊酸钠联合鲁拉西酮治疗双相障碍抑郁发作的疗效及对血清催乳素的影响

目的:研究丙戊酸钠联合鲁拉西酮治疗双相障碍抑郁发作的疗效及对血清催乳素(PRL)的影响。方法:按随机数表法将100例双相障碍抑郁发作患者分为观察组和对照组,各50例。两组分别采用鲁拉西酮、丙戊酸钠联合鲁拉西酮治疗。比较两组临床疗效、促甲状腺激素(TSH)、PRL、雌二醇(E2)水平、自知力与治疗态度问题(ITAQ)评分、正负性情绪量表(PANAS)评分、不良反应发生率。结果:两组有效率分别为95.65%、81.40%,两组有效率比较差异有统计学意义(P<0.05)。治疗后观察组正性情绪评分高于对照组、负性情绪评分低于对照组,并且观察组治疗前后PANAS评分差值较高(P<0.05)。治疗后两组PRL、E2有所升高且观察组高于对照组,此外观察组治疗前后TSH、PRL、E2水平差值较高(P<0.05)。治疗后两组ITAQ评分增高,观察组ITAQ评分高于对照组,此外观察组治疗前后ITAQ评分差值较高(P<0.05)。结论:丙戊酸钠联合鲁拉西酮用于双相障碍抑郁发作疗效好,能改善患者的情绪状态,增加血清PRL水平,提高患者认知能力,且安全性较高。

22nm全耗尽型绝缘体上硅器件单粒子瞬态效应的敏感区域

基于3D-TCAD模拟,研究了22 nm全耗尽型绝缘体上硅(fully depleted silicon-on-insulator,FDSOI)器件单粒子瞬态(single-event transient,SET)效应的敏感性区域。对比了使用单管和使用反相器来研究器件SET敏感性区域的方法,从而分析实际电路中重离子轰击位置对22 nm FDSOI器件SET敏感性的影响,并从电荷收集机制的角度进行了解释。深入分析发现寄生双极放大效应对重粒子轰击位置敏感是造成器件不同区域SET敏感性不同的原因。而单管漏极接恒压源造成漏极敏感性增强是导致单管与反相器中器件SET敏感区域不同的原因。修正了FDSOI工艺下器件SET敏感性区域的研究方法,与单管相比,采用反相器进行仿真,结果更符合实际情况,这将为器件SET加固提供理论指导。

基于锗硅异质结双极晶体管的低噪声放大器及其反模结构的单粒子瞬态数值仿真研究

针对锗硅异质结双极晶体管(SiGe HBT)进行TCAD仿真建模,基于SiGe HBT器件模型搭建低噪放大器(LNA)电路,开展单粒子瞬态(SET)的混合仿真,研究SET脉冲随离子不同LET值、入射角度的变化规律.结果表明:随着入射离子LET值的增大,LNA端口的SET脉冲的幅值增大,振荡时间延长;随着离子入射角的增大,LNA端口的SET脉冲的幅值先增大后减小,振荡时间减小.使用反模(IM)共射共基结构(Cascode)降低LNA对单粒子效应的敏感度,验证了采用IM结构的LNA电路的相关射频性能.针对离子于共基极(CB)晶体管、共发射极(CE)晶体管两种位置入射进行SET实验.实验结果与本实验中的正向模式相比,IM Cascode结构的LNA电路的瞬态电流持续时间明显减少,并且峰值减小了66%及以上.

BCD工艺中大电流下纵向双极晶体管的电流集边效应研究

在大电流条件下,随着电流密度的增加,发射区结电流集边效应、基区电导调制效应、基区展宽效应会随之出现。基于研究单位的BCD工艺,在集成CMOS和DMOS的基础上集成功率纵向NPN双极晶体管用于输出。设计了75μm×4μm、50μm×6μm、30μm×10μm三种不同尺寸的发射极并进行TCAD仿真研究。在发射极面积相同的情况下,发射极长宽比越小,TCAD可观察到的电流集边效应越严重,最终流片并进行测试验证,得出75μm×4μm的细长结构尺寸能够提升晶体管在大电流下的放大能力,较30μm×10μm的结构提升约11.4%。

丙戊酸盐治疗成人双相情感障碍中的血药浓度与疗效分析

目的探讨丙戊酸盐治疗成人双相情感障碍中的血药浓度与临床疗效。方法回顾性分析2021年1月至2023年4月我院收治的成人双相情感障碍60例患者的临床资料,所有患者均给予丙戊酸盐治疗,观察患者年龄、性别、体重、合并用药及给药剂量对丙戊酸盐血药浓度的影响,探讨丙戊酸盐血药浓度与临床疗效及不良反应的关系。结果患者年龄、体重、性别对丙戊酸血药浓度影响不明显;给药剂量在0.75~1 g/d时,平均血药浓度为(95.97±24.26)μg/mL,可达到最佳量效;合并用药数量增加,丙戊酸血药浓度降低;丙戊酸盐的不良反应发生率38.75%,血药浓度和不良反应发生率成正相关性,丙戊酸血浓度>120μg/mL时,不良反应显著增加;经spearman相关分析,浓度与疗效之间存在正相关关系,当丙戊酸钠浓度处于50~120μg/mL时可达到最佳疗效。结论丙戊酸盐治疗阈浓度在50~120μg/mL范围内安全有效。定期监测血药浓度可作为使用丙戊酸盐的成人双相情感障碍患者及时合理调整药物剂量的参考,为实施个体化给药方案提供依据。

拉莫三嗪联合重复经颅磁刺激治疗双相情感障碍临床研究

目的探讨拉莫三嗪联合重复经颅磁刺激治疗双相情感障碍的临床效果。方法将82例双相情感障碍患者按照随机数字表法分为对照组41例与研究组41例。对照组患者给予拉莫三嗪治疗,研究组给予拉莫三嗪联合重复经颅磁刺激治疗。比较两组患者治疗前后贝克-拉范森躁狂量表(BRMS)、简明精神病评定量表(BPRS)、汉密顿抑郁量表(HAMD)、蒙特利尔认知评估量表(MoCA)、个人与社会功能量表(PSP)、持续操作测验量表(CPT)、匹兹堡睡眠质量指数(PSQI)、生活质量综合评价问卷(GQOLI-74)评分以及两组患者治疗后的临床疗效和不良反应发生率。结果研究组患者治疗总有效率高于对照组(P<0.05)。治疗后两组患者BRMS、BPRS、HAMD、PSQI评分均较治疗前降低,且研究组低于对照组(P<0.01)。治疗后两组患者MoCA、PSP、CPT评分及GQOLI-74各维度评分均较治疗前升高,且研究组高于对照组(P<0.05或0.01)。结论拉莫三嗪联合重复经颅磁刺激治疗双相情感障碍临床疗效显著,安全性高,能显著改善患者认知功能、抑郁症状、躁狂症状、睡眠质量及生活质量,值得临床推广应用。

双极晶体管空间辐射效应的研究进展

双极晶体管具有电流驱动能力强、噪声低、线性度高等优点,已成为航天飞行器中常用的电子元器件。然而,在空间辐射环境下服役时,双极晶体管容易发生性能退化,进而危及航天设备的运行。因此,本文综述了双极晶体管在空间辐射环境中产生的损伤效应,主要包含电离损伤效应、位移损伤效应以及电离/位移损伤协同效应,并分析了双极晶体管的性能退化规律以及损伤机理,从而为双极晶体管的抗辐射研究提供一定的参考。

富血小板血浆联合双极射频点阵治疗毛孔粗大的临床效果

目的观察富血小板血浆(PRP)联合双极射频点阵治疗毛孔粗大的临床效果。方法选择2022年5月至2023年5月武汉大学中南医院收治的90例毛孔粗大患者,以随机数字表法将其分为PRP组(30例,PRP治疗)、双极射频点阵组(30例,双极射频点阵治疗)、联合组(30例,PRP联合双极射频点阵治疗)。比较各组临床疗效;比较各组治疗前后皮肤检测仪特征、皮肤生理功能;记录三组不良反应发生情况。结果联合组疗效优于PRP组、双极射频点阵组(P<0.05)。治疗后,三组斑点、红色区、毛孔、皱纹、紫外线色斑、棕色斑、油脂、黑色素、红斑、经皮水分流失评分低于治疗前,且联合组低于PRP组、双极射频点阵组(P<0.05);治疗后,三组纹理、水分评分均高于治疗前,且联合组高于PRP组、双极射频点阵组(P<0.05)。联合组不良反应总发生率低于PRP组、双极射频点阵组(P<0.05)。结论PRP联合双极射频点阵治疗毛孔粗大效果显著,可改善皮肤整体特征,提升皮肤生理功能。

铝材极板冲压成形晶体塑性有限元仿真分析

为研究双极板微成形过程中的尺寸效应问题,采用多通道结构,选用0.1 mm厚的1060纯铝片作为研究材料,通过Neper软件建立不同晶粒尺寸的多晶Voronoi模型,利用Python脚本为每个晶粒赋予随机取向,以模拟微冲压变形过程。通过晶体塑性有限元仿真成形研究晶粒尺寸对微冲压过程和质量的影响,包括极限成形深度、载荷-行程关系、尺寸精度以及成形厚度分布等方面。研究结果表明:随着晶粒尺寸的增加,板材极限成形深度在减小,最大变形载荷逐渐减小,厚度分布也更加不均匀,尤其是在拐角区域出现最薄的位置。

氟西汀联合奥氮平在治疗双相抑郁中的应用

目的探讨奥氮平联合氟西汀对双相抑郁症患者的临床效果和不良反应。方法选取2020年1月—2021年1月本院收治的110例双相抑郁症患者为研究对象,按治疗方式将其分成对照组和观察组,每组55例。其中,对照组应用奥氮平治疗,观察组应用奥氮平联合氟西汀治疗,两组疗程为期2个月。对比两组患者的治疗效果、治疗前后的抑郁和焦虑评分以及不良反应。结果观察组治疗后的临床有效率明显优于对照组,差异有统计学意义(P=0.038)。两组患者在治疗2个月后的抑郁症和焦虑症得分较治疗之前均有下降,而观察组较对照组下降更明显,差异有统计学意义(P<0.001)。对照组不良反应发生率高于观察组,差异有统计学意义(P<0.001)。结论双相抑郁的治疗中应用氟西汀联合奥氮平治疗效果明显,可有效缓解患者的情绪,减少不良反应,非常值得临床推广应用。