非晶碳/Mo_2C混合膜冷阴极FED发光显示

对Al2O3陶瓷衬底进行粒度为W20的金刚砂机械抛光,采用磁控溅射方法镀过渡层Mo,对其表面进行Nd∶YAG激光刻蚀处理。最后在微波等离子体增强化学汽相沉积(MPCVD)反应腔中在一定条件下沉积了薄膜,反应气体为CH4和H2。从样品的Raman谱可以看出薄膜有非晶碳成分。样品XRD谱线中有比较明显的晶态Mo2C衍射峰。所制备的样品为非晶碳/Mo2C混合结构薄膜。在高真空室中测量了样品的场发射特性,其开启场强为0.55V/μm,在1.8V/μm电场下测得样品的场发射电流密度为6.8mA/cm2。由样品CCD照片观察其发射特性可以看出,样品发射点密度随场强的增大而增加,发射点比较均匀。同时计算样品在2.2V/μm场强下样品发射点密度大于103/cm2。实验表明该薄膜是一种好的场致电子发射体。     

0．5μm OTP工艺开发与器件特性研究

文章对0．5μm一次编程存储器（OTP）存储单元的器件结构、工艺流程、存储单元器件特性及可靠性提高等方面进行了研究。在一定的编程条件下,编程0．1ms时器件的阈值电压能够大于6V,控制栅或漏极加电压10s时阈值电压退化量小于0．1V,因此器件的编程速度和编程串扰特性能够满足要求。通过改善浮栅和控制栅层间介质氧化硅-氮化硅-氧化硅（ONO）的质量及采用存储单元覆盖氮化硅保护层等优化措施,存储单元的数据保持能力能够大于10年。     

4H-SiC埋沟MOSFET的研制

研制了4H-SiC热氧化生长氧化层埋沟nMOSFET.用室温下N离子注入的方法形成埋沟区和源漏区,然后在1600℃进行激活退火.离子注入所得到的埋沟区深度大约为0.2μm.从转移特性提取出来的峰值场效应迁移率约为18.1cm2/(V·s).造成低场效应迁移率的主要因素可能是粗糙的器件表面(器件表面布满密密麻麻的小坑).3μm和5μm器件的阈值电压分别为1.73V和1.72V.3μm器件饱和跨导约为102μS( V G=20V, V D=10V).     

MOCVD生长的SiC衬底高迁移率GaN沟道层AlGaN/AlN/GaN HEMT结构

用MOCVD技术在高阻6H-SiC衬底上研制出了具有高迁移率GaN沟道层的AlGaN/AlN/GaN高电子迁移率晶体管(HEMT)结构材料,其室温和80K时二维电子气迁移率分别为1944和11588cm2/(V·s),相应二维电子气浓度为1.03×1013cm-2;三晶X射线衍射和原子力显微镜分析表明该材料具有良好的晶体质量和表面形貌,10μm×10μm样品的表面粗糙度为0.27nm.用此材料研制出了栅长为0.8μm,栅宽为1.2mm的HEMT器件,最大漏极饱和电流密度和非本征跨导分别为957mA/mm和267mS/mm.     

ZnO和Al2O3缓冲层对AZO透明导电膜薄膜性能的影响

采用射频磁控溅射法,以纯度为99.9%,质量分数98%ZnO、2%Al2O3陶瓷靶为溅射靶材,在预先沉积了ZnO和Al2O3的玻璃衬底上制备了Al2O3掺杂的ZnO薄膜。研究并对比了两种不同的缓冲层对ZnO∶Al(AZO)薄膜的微观结构和光电性能的影响。并借助X线衍射(XRD)仪、扫描电子显微镜(SEM)、紫外可见光谱仪(UV-Vis)等方法测试和分析了不同缓冲层,对AZO薄膜的形貌结构、光电学性能的影响。结果表明:加入缓冲层后,在衬底温度为200℃时,溅射30min,负偏压为60V、在氮气气氛下经300℃退火处理后,制得薄膜的可见光透过率为83%～87%,AZO薄膜的最低电阻率,从9.2×10-4Ω.cm(玻璃)分别下降到8.0×10-4Ω.cm(ZnO)和5.4×10-4Ω.cm(Al2O3)。     

输出功率密度为2.23W/mm的X波段AlGaN/GaN功率HEMT器件

MOCVD技术在蓝宝石衬底上制备出具有高迁移率GaN沟道层的AlGaN/GaN HEMT材料.高迁移率GaN外延层的室温迁移率达741cm2/(V·s),相应背景电子浓度为1.52×1016cm-3;非有意掺杂高阻GaN缓冲层的室温电阻率超过108Ω·cm,相应的方块电阻超过1012Ω/□.50mm HEMT外延片平均方块电阻为440.9Ω/□,方块电阻均匀性优于96％.用此材料研制出了0.2μm栅长的X波段HEMT功率器件,40μm栅宽的器件跨导达到250mS/mm,特征频率fT为77GHz;0.8mm栅宽的器件电流密度达到1.07A/mm,8GHz时连续波输出功率为1.78W,相应功率密度为2.23W/mm,线性功率增益为13.3dB.     

Peltier effect in doped silicon microchannel plates

The Seebeck coefficient is determined from silicon microchannel plates（Si MCPs） prepared by photoassisted electrochemical etching at room temperature（25℃）.The coefficient of the sample with a pore size of 5×5μm²,spacing of 1μm and thickness of about 150μm is -852μV/K.along the edge of the square pore.After doping with boron and phosphorus,the Seebeck coefficient diminishes to 256μV/K and -117μV/K along the edge of the square pore,whereas the electrical resistivity values are 7.5×10^-3Ω·cm and 1.9×10^-3Ω·cm,respectively. Our data imply that the Seebeck coefficient of the Si MCPs is related to the electrical resistivity and is consistent with that of bulk silicon.Based on the boron and phosphorus doped samples,a simple device is fabricated to connect the two type Si MCPs to evaluate the Peltier effect.When a proper current passes through the device,the Peltier effect is evidently observed.Based on the experimental data and the theoretical calculation,the estimated intrinsic figure of merit ZT of the unicouple device and thermal conductivity of the Si MCPs are 0.007 and 50 W/（m·K）, respectively.     

Synthesis and Crystal Structure of Novel Emitting Material 9,9-Bis(buthoxycarbonylethyl) fluorene

Synthesis of 9,9-bis(buthoxycarbonylethyl)fluorine(C27H34O4, Mr=422.54) with butyl acrylate as alkylation reagent and fluorene as starting material has been performed. The crystal structure was measured by using the X-ray diffraction method.The crystal belongs to monoclinic, space group P2(1)/c with parameters as: a=1.2912(1)nm, b=1.0974(1)nm, c=1.7468(1)nm, β=90.252(2), V=2.4752(4)nm3, Z=4, Dcacl=1.134 g·cm-3, λ=0.071 073 nm, μ(MoKα)=0.075mm-1, F(000)=912, R=0.0651 and wR=0.1475. X-ray analysis reveals tha...     

Effects of Al2O3 Dielectric Cap and Nitridation on Device Performance, Scalability, and Reliability for Advanced High- κ/Metal Gate pMOSFET Applications

A pFET threshold-voltage (Vt) reduction of about 200 mV is demonstrated by inserting a thin Al₂O₃ layer between the high-k dielectric and the TiN gate without noticeable degradation of other electrical properties. HfSiO_propcapped with 9 Aring of thin Al₂O₃obtains a low long-channel Vt of -0.37 V (the lowest among those with TiN gate), a high mobility of 59 cm² /V ldr s at 0.8 MV/cm (92% of universal value), a negligible equivalent- oxide-thickness (EOT) increase of 0.1 Aring (compared to the uncapped reference), and a low Vt instability of 4.8 mV at 7 MV/cm. It also passes the ten-year negative-bias-temperature-instability (NBTI) lifetime specification with a gate overdrive of -0.7 V. This indicates that thin Al₂O₃obtains caps are beneficial to the pFET applications. In contrast, nitrogen incorporation in the Al₂O₃-capped HfSiO_prop is not favorable because it increases the Vt by 50-140 mV, degrades the mobility by 10%-22%, increases the EOT by 0.5-0.8 Aring and the Vt instability by 5-13 mV, and reduces the NBTI lifetime by four to five orders of magnitude. Compared to postcap nitridation, high-k nitridation results in more severe degradation of these properties by incorporating nitrogen closer to the Si/SiO₂ interface.     

Improvement of the field emission properties of carbon nanotubes by CNT/Fe_3O_4 composite electrophoretic deposition

A simple CNT/Fe_3O_4 composite electrophoretic deposition method to improve the field emission cathode properties of carbon nanotubes(CNTs) is proposed.It is found that CNT/Fe_3O_4 composite electrophoretic deposition leads to better field emission performance than that of single CNT electrophoretic deposition.The result is investigated using SEM,J-E and FE.After the process,the turn-on electric field decreases from 0.882 to 0.500 V/μm at an emission current density of 0.1 mA/cm~2,and the latter increase...     

用过氧化氢后处理多孔硅厚膜的一种新技术

提出使用过氧化氢后处理多孔硅厚膜.在乙醇、氢氟酸、过氧化氢溶液中,多孔硅样片做阴极施加电流密度为10mA/cm2,希望通过后处理增强多孔硅表面的稳定性、光滑度和机械强度.研究了厚度为20μm和70μm的多孔硅厚膜经过过氧化氢处理后的微结构.扫描电镜图显示经过过氧化氢处理后的多孔硅厚膜表面的光滑度有极大的提高,X光衍射光谱揭示经过过氧化氢后处理后多孔硅表面形成了一层氧化膜.     

A new high-voltage tolerant I/O for improving ESD robustness

A new design scheme to improve the ESD performance of high voltage tolerance (HVT) I/O is presented in this paper. Without calling for the additional process steps or modification, the proposed design enhances the ESD failure immunity by having both of the stacked nMOS transistors turned on simultaneously. The ESD characteristic of new HVT IO structure has been measured using TLP and shows the improvement in It2 to 2.2A from 0.5 A and Vt1 to 6.1 V from 11.5 V, respectively.     

连续波可调谐CO2激光在AgGaSe2中倍频研究

在一台小型连续波(CW)CO2激光器上用光栅调谐获得了从9.23-10.65μm范围内20条谱线输出,用一片8 mm×8 mm×15 mm红外非线性光学晶体AgGaSe2实现了上述谱线的二倍频输出。实验测得10P(20)谱线的倍频光输出为2.1μW,相位匹配接收外角△θ外·L=2.1°·cm。     

Depletion Mode HEMT with Refractory Metal Silicide WSi Gate

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外腔面发射激光器GaAs基质的酸性腐蚀

外腔面发射激光器的GaAs基质厚度大,热导率低,严重阻碍有源区热量的扩散,影响激光器功率的提高。为了去除激光器的GaAs基质,采用硫酸系酸性腐蚀,通过改变腐蚀液浓度和腐蚀温度来比较腐蚀液对GaAs基质的腐蚀影响,并采用原子力显微镜照片表征了腐蚀表面的粗糙度。结果表明,当腐蚀液的体积比V（H2SO4）:V（H2O2）:V（H2O）=1:5:10,腐蚀温度为30℃时,腐蚀速率适中,为5.2μm/min,腐蚀表面粗糙度2.7nm,腐蚀总体效果较为理想。较好的GaAs基质腐蚀效果为外腔面发射激光器衬底去除腐蚀阻挡层的选择性腐蚀提供了基本的保障。     

RF-MBE生长的AlGaN/GaN高电子迁移率晶体管特性

用射频分子束外延技术研制出了室温迁移率为1035cm2/(V·s),二维电子气浓度为1.0×1013cm-2,77K迁移率为2653cm2/(V·s),二维电子气浓度为9.6×1012cm-2的AlGaN/GaN高电子迁移率晶体管材料.用此材料研制的器件(栅长为1μm,栅宽为80μm,源-漏间距为4μm)的室温非本征跨导为186mS/mm,最大漏极饱和电流密度为925mA/mm,特征频率为18.8GHz.     

酞菁裂解法制备定向碳纳米管阵列及其场发射性能研究

碳纳米管作为一种新型的光电材料有着广泛的应用,可用于平板显示器中的电子发射器件。定向碳纳米管阵列是碳纳米管的一种取向形态,具有其独特的性质。与缠绕无序的碳纳米管相比,定向碳纳米管更易分散、测量和应用。文章在低压条件下采用酞菁铁高温裂解法,在800～1000℃,以石英玻璃为基底,制备了大面积高度定向的碳纳米管。通过SEM和TEM对定向碳纳米管的结构进行分析。结果表明该法制备的碳纳米管长20μm,管径40～70nm,为竹节状结构的多壁碳纳米管。实验中发现系统真空度和生长温度都对定向碳纳米管生长有影响。通过对该碳纳米管进行场发射测试,结果表明此定向碳纳米管的开启电压仅为0.67V.μm-1(I=1μA),阈值电压为2.5V.μm-1,具有良好的场发射性能。     

Electron Mobility in Tris（8—Hydroxyquinolinolato）Aluminum Thin Film Based on Silicium^①②

We have measured the mobilities of electrons in thin,vapor-deposited films of tris(8-hydroxyquinolinolato) aluminum(Alq 3) based on silicium using a time-of-flight(TOF) technique.The drift of electron mobility is strongly electric field and temperature dependent.At room temperature and an electric field of 2×10 5 V·cm -1 ,the effective mobility of electron is 1.0×10 -5 cm 2·V -1 ·s -1 for 200 nm thick sample.     

0.5μm部分耗尽SOI NMOSFET热载流子可靠性研究

对0.5μm部分耗尽SOI NMOSFET热载流子的可靠性进行了研究。在Vds=5V,Vgs=2.1V的条件下,加电1 000s后,宽长比为4/0.5的部分耗尽SOI H型栅NMOSFET的前栅阈值电压的漂移(ΔVt/Vt)和跨导的退化(Δgm/gm)分别为0.23%和2.98%。以器件最大跨导gm退化10%时所对应的时间作为器件寿命,依据幸运电子模型,0.5μm部分耗尽SOI NMOSFET寿命可达16.82年。     

Hole Mobility in Poly（N—vinylcarbazole） Thin Film Based on Silicium^①②

The mobilities of holes in thin,spin-casting films of poly( N -vinylcarbazole)(PVK) based on silicium are measured using a time-of-flight (TOF) technique.The drift of hole mobility is strongly dependent on the electric field and temperature.At room temperature and an electric field of 2×10 5 V·cm -1 ,the effective mobility of hole is 7.14×10 -6 cm 2·V -1 ·s -1 ,in a 200 nm thick sample.