还原再氧化型半导体陶瓷电容器材料的研究

通过实验研究了Ｎｄ２Ｏ３、Ｎｂ２Ｏ５、Ｓｍ２Ｏ３添加量对还原再氧化型ＢａＴｉＯ３半导体陶瓷电容器材料性能的影响，同时优化了烧结工艺，获得了Ｃ＞０．５μＦ／ｃｍ２，ｔｇδ＜３．５×１０－２，ρ＞４×１０１１Ω·ｃｍ，｜△Ｃ／Ｃ｜（－２５～＋８５℃）＜＋３０－８０％，Ｖｂ＞４２０Ｖ的实用半导体陶瓷电容器材料     

高温超导GdBa2Cu3O7—δ薄膜双晶晶界结及光探测器

在晶界夹角为２４°的Ｚｒ（Ｙ）Ｏ２人工双晶基片上制备高温超导双晶Ｇｄ－Ｂａ２Ｃｕ３Ｏ７－δ薄膜，用光刻技术在晶界上刻出１０×１０ｍ２的双晶晶界结，它与外电路一起构成光探测器。在８０Ｋ用Ｈｅ－Ｎｅ激光和５００Ｋ黑体作为辐射源测量了光探测器的响应特性。探测结果：噪声等效功率ＮＥＰ分别为６．７×１０－１４和３．８×１０１４ＷＨｚ－１／２，归一化探测率分别为１．４×１０１０和２．６×１０１０ｃｍＨｚ１／２Ｗ－１；响应度分别为１．８×１０７和３．２×１０７ＶＷ－１。     

YBa_2Cu_3O_（7－δ）高温超导薄膜线列探测器的研究

采用准分子激光扫描消融法淀积性能均匀的ＹＢａ_２Ｃｕ_３Ｏ_（７－δ）高温超导薄膜，用离子束刻蚀进行器件的图形制备，获得了非均匀性小于１０％的ＹＢａ_２Ｃｕ_３Ｏ_（７－δ）高温超导薄膜８元线列探测器．测试了器件在８～１４μｍ波段的性能及光响应特性，单元探测器为４０×１００μｍ２的微桥结构．器件的平均归一化探测率为１．４４×１０９ｃｍＨｚ１／２ｗ－１，平均噪声等效功率为４．４×１０－１２ＷＨｚ－１／２，Ｄ的非均匀性小于１０％．研究结果表明：该线列探测器具有良好的均匀性，证实了该工艺适用于制备均匀性良好的高温超导薄膜红外探测器阵列．     

高TcGdBa2Cu3O7—δ薄膜双晶结光探测器

研制了具有约瑟夫逊效应的高ＴｃＧｄＢａ２Ｃｕ３Ｏ７－δ薄膜双晶晶界结，按照光助隧道效应的原理我们用双晶结进行光探测，光源是波长为０．６３２８μｍ的Ｈｅ－Ｎｅ激光器，系统观测了高Ｔｃ ＧｄＢａ２Ｃｕ３Ｏ７－δ双晶结的光响应特性，最好的结果为：噪声等效功率ＮＥＰ＝４．３×１０＾－１４ＷＨｚ＾－１／２，归一化探测率Ｄ＾８＝１．２×１０＾１０ｃｍＨｚ＾１／２Ｗ＾－１，响应率Ｒｖ＝３．５×１０＾７Ｖ／Ｗ，     

In0.53Ga0.47As／InP异质结光电二极管的深能级

采用深能级瞬态谱仪（ＤＬＴＳ）测定了Ｉｎ０．５３Ｇａ０．４７Ａｓ／ＩｎＰ异质结光电二极管的ＤＬＴＳ谱。发现存在一电子陷阱，该陷阱能级位于导带底以下０．４４ｅＶ处，能级密度为３．１０×１０１３ｃｍ－３，电子俘获截面为１．７２×１０－１２ｃｍ－２。由于深能级的存在，导致了该器件存在一种新的“暗电流”──“深能级协助隧穿电流”。     

有机薄膜衬底ITO透明导电膜的结构和光电特性

我们用反应蒸发法在氧分压２×１０－２Ｐａ、衬底温度８０～２４０℃条件下蒸发铟－锡合金，在有机薄膜衬底上制备出ＩＴＯ膜，并研究了其结构和光电特性随制备衬底温度的变化．制备膜的最佳取向为（１１１）方向，迁移率为２０．７～３６．７ｃｍ２·Ｖ－１·ｓ－１，载流子浓度为（１．７～４．４）×１０２０ｃｍ－３，适当调节制备参数，可得电阻率为６．６３×１０－４Ω·ｃｍ、在可见光区透过率达８２％的有机薄膜衬底ＩＴＯ膜     

YBCO薄膜红外探测器研究的新进展

用ＹＢＣＯ／ＬａＡｌＯ＿３薄膜制成的１ｍｍ红外探测器，经技术保护之后，寿命已达３年。其Ｄ（５００，１０，１）＝３．７×１０￣９ｃｍＨｚ￣（１／２）Ｗ￣（－１），ＮＥＰ（５００，１０，１）＝２．４×１０￣（－１１）ＷＨｚ￣（－１／２）；超导微桥（５０μｍ×１０μｍ）红外探测器，其Ｄ（５００，１０，１）＝１×１０￣９ｃｍＨｚ￣（１／２）Ｗ￣（－１），ＮＥＰ（５００，１０，１）＝２．３×１０￣（－１２）ＷＨｚ￣（－１／２）。     

掺Cr^4＋饱和吸收体吸收截面和基态恢复时间的测量

本文给出一种测量掺Ｃｒ＾４＋饱和吸收体基态和激光发态吸收截面的方法，并用之测量国产Ｃｒ＾４＋：ＹＡＧ的两个吸收截面分别为４．３×１０＾－１８ｃｍ＾２和８．２×１０＾１９ｃｍ＾２；同时给出一种用泵浦探测法测量可饱和吸收体μｓ量级基态恢复时间的方法，并用之测得国产Ｃｒ＾４＋：ＹＡＧ的基态恢复时间为３．２μｓ。     

大电流(直流)冲击试验对-族氮化物异质结深电子态的影响

利用电流电压（ＩＶ）、电致发光（ＥＬ）和深能级瞬态傅里叶谱（ＤＬＴＦＳ）技术研究ⅢⅤ族氮化物基异质结深电子态．观察到大电流（直流）冲击引起电流电压和电致发光特性的弛豫．ＤＬＴＦＳ研究表明,电流冲击之前,样品存在一个位于导带下１１ｅＶ处深能级（Ｅ１）,它具有２７×１０１３ｃｍ－３浓度和５×１０－１４ｃｍ２俘获截面．经电流冲击（７７Ｋ,２００ｍＡ和４０ｍｉｎ）后,Ｅ１浓度为４２１×１０１３ｃｍ－３,约增加了２倍．实验结果表明Ｅ１浓度的增加与样品ＩＶ、ＥＬ特性弛豫是一致的     

两步快退火改善InP（Fe）中MeV硅注入层的品质

２ＭｅＶ、（１～２）×１０１４ｃｍ－２硅离子注入ＳＩ－ＩｎＰ（Ｆｅ）造成负的（－３．４×１０－４～－２．９×１０－４）晶格应变，光快速退火的激活能为０．２６ｅＶ。８８０℃／１０ｓ退火可得到１００％的施主激活。间断两步退火（３７５℃／３０ｓ＋８８０℃／１０ｓ）使注入层单晶恢复完全，较大程度（２０％～３５％）地改善了载流子的迁移率。四能量叠加注入已能在０．５～３．０μｍ的深度区域形成满足某些器件要求的低电阻（７．５Ω）高浓度［（２～３）×１０１８ｃｍ－３］的ｎ型导电层。     

FLOTOXEEPROM擦写过程中隧道氧化层陷阱俘获电荷的研究

本文首先从理论上分析FLOTOX EEPROM隧道氧化层中陷阱俘获电荷对注入电场和存储管阈值电压的影响,然后给出了在不同擦写条件下FLOTOX EEPROM存储管的阈值电压与擦写周期关系的实验结果,接着分析了在反复擦写过程中陷阱俘获电荷的产生现象.对于低的擦写电压,擦除阈值减少,在隧道氧化层中产生了负的陷阱俘获电荷;对于高的擦写电压,擦除阈值增加,产生了正陷阱俘获电荷.这一结果与SiO₂中电荷的俘获——解俘获动态模型相吻合.     

Trapped-electron and generated interface-trap effects in hot-electron-induced MOSFET degradation

A new experimental method is proposed to distinguish the electron-trapping effect in the gate oxide from the interface-trap generation effect in hot-electron-induced nMOSFET degradation. In this method, by selecting the appropriate bias conditions, hot electrons and/ or hot holes are intentionally injected into the oxide region above the channel outside the drain layer, which affects MOSFET characteristics such as threshold voltage and transconductance. The negative charges of electrons trapped in the oxide during hot-electron injection are completely compensated for by the positive charges of subsequently injected and trapped holes, and the trapped electron effect in the degradation is eliminated. Using this method, the causes for hot-electron-induced transconductance degradation (Δgm/gm) are analyzed. As the degradation increases, the trapped-electron effect decreases, and the generated interface-trap effect increases. The relationship of (Δgm/gm)_{it}, =A(Δgm/gm) --Bis obtained, where (Δgm/gm)_{it} is gmdegradation due to generated interface-traps, andAandBare fixed numbers. Furthermore φ_{it}/λ (the ratio of the critical value in hot-electron energy for interface-trap generation to the mean free path of hot electrons in Si) is experimentally obtained to be 5.7 × 10⁶eV/cm. Using λ = 9.2 nm [1], a value of φ_{it} = 5.2 eV is derived.     

Anodic oxidation of Si in oxygen/chlorine plasma

By adding a few percent of chlorine to oxygen plasma, the anodization rate of Si was enhanced; for example, the rate was doubled for oxygen containing 3-percent chlorine. With a chlorine concentration of 1.5 percent, the density of trap states at the Si-SiO2interface was reduced from 7×10¹¹/cm².eV to 5×10¹¹/cm².eV at the midgap of Si; after annealing at 800°C in argon for 60 min, it was reduced to 8 × 10¹⁰/cm².eV, and did not return to the original value after heating the specimen to 800°C. The density and capture cross section of traps in plasma-anodic oxide were also measured using the constant-current avalanche-injection method. The number of electron traps with small cross sections in plasmaanodic SiO2films was reduced by annealing them at 800°C in argon, but SiO2films which were anodized in oxygen/chlorine plasma showed an increase of trap density under the same annealing condition.     

Assessment of capture cross sections and effective density of electron traps generated in silicon dioxides

Generation of acceptor-like electron traps in gate oxides is an important source for device instability. Despite previous efforts, capture cross sections are not unambiguously determined, and there is confusion on how many capture cross sections genuinely exist. Neither is the dependence of trap density for a given capture cross section on stress level clear. The objective of this paper is to fill this knowledge gap by investigating electron-trapping kinetics. There are a number of obstacles for such an investigation including the simultaneous occurrence of trapping and trap generation, stability of trapping, and effects of positive charges. Through careful selection of experimental conditions and testing samples, the authors have been able to overcome these obstacles. In particular, their recent work in this area has allowed them to develop a new method for correcting the effect of positive charges. After removing all uncertainties, the authors are able to identify a capture cross section as large as 10/sup -13/-10/sup -14/ cm/sup 2/ for the generated acceptorlike trap. It will be shown that electron trapping follows the first-order model, and there is also a smaller capture cross section in the region of 10/sup -15/-10/sup -16/ cm/sup 2/. To the best of their knowledge, for the first time, the authors will show that the density of the larger trap increases with stress, but the density of the smaller trap clearly saturates.     

Thermal emission rates and capture cross sections of majority carriers at vanadium centers in silicon

The thermal emission rates and capture cross sections of majority carriers on the vandium associated centers in the depletion region of reverse biased silicon p-n junctions have been measured by the dark capacitance transient method. The three vanduim associated levels observed, two donor levels and a deep acceptor level, belong to the same vandium center. Least square fits of the emission data give the following emission rates; e_nl^t = 1.047 × 10⁶T² exp [?0.179±0.004 eV/kT], e_n0^t = 3.55 × 10⁷T² exp [?0.426±0.004 eV/kT] and e_p-2^t = 1.514 × 10⁶T² exp [?0.450±0.003 eV/kT]. The activation energy of the hole emission rate at the lower donor level is about 0.1 eV larger than the equilibrium thermal activation energy. The capture cross sections are σ_n0 = 3 × 10^?17cm² and σ_p0 = 8 × 10^?16cm² for the electron capture process at the deep acceptor level and the hole capture process at the upper donor level, respectively. The hole capture cross section on the lower donor level (σ_p-1) depends significantly on temperature. The large temperature dependence of the hole capture cross section can be expected due to the nonradiative multiphonon emission process.     

Sulphur doped silicon IR detectors

Experimental data on the electrical transport properties and photoconductive detector performance of sulphur doped silicon as a function of temperature are presented. Analysis of the data shows that the detector performance is determined by a donor level at 0.19 eV from the conduction band edge with an electron capture cross section of 2 × 10^?13 cm² and a peak photoionization cross section of 1 × 10^?16 cm². Photoconductivity has been observed at 95 K which may be associated with a centre 0.37 eV below the conduction band.     

Effects of Illumination on Ar<Superscript>+</Superscript>-Implanted <Emphasis Type="Italic">n</Emphasis>-Type 6H-SiC Epitaxial Layers

Argon ions were implanted into n-type 6H-SiC epitaxial layers at 600°C. Postimplantation annealing was carried out at 1,600°C for 5 min in an Ar ambient. Four implantation-induced defect levels were observed at E_C-0.28 eV, E_C-0.34 eV, E_C-0.46 eV, and E_C-0.62 eV by deep level transient spectroscopy. The defect center at E_C-0.28 eV is correlated with ED₁/ED₂ and with ID₅. The defect at E_C-0.46 eV with a capture cross section of 7.8 × 10⁻¹⁶ cm² is correlated with E1/E2, while the defect at E_C-0.62 eV with a capture cross section of 2.6 × 10⁻¹⁴ cm² is correlated with Z1/Z2. Photo deep level transient spectroscopy was also used to study these defects. Upon illumination, the amplitudes of the deep level transient spectroscopy (DLTS) peaks increased considerably. Two emission components of Z1/Z2 were revealed: one fast and the other slow. The fast component could only be observed with a narrow rate window. In addition, a new defect was observed on the low-temperature side of the defect at E_C-0.28 eV when the sample was illuminated. [rl](Received ...; accepted ...)     

湿N2退火HfTiO和HfO2栅介质 Ge MOS电特性研究

采用反应磁控溅射方法在Ge衬底上分别制备了HfTiO和HfO2高κ栅介质薄膜,并研究了湿N2和干N2退火对介质性能的影响。由于GeOx在水气氛中的水解特性,湿N2退火能分解淀积过程中生长的锗氧化物,降低界面态和氧化物电荷密度,有效提高栅介质质量。测量结果表明,湿N2退火Al/HfTiO/n-GeMOS和Al/HfO2/n-GeMOS电容的栅介质等效厚度分别为3.2nm和3.7nm,-1V栅偏压下的栅极漏电流分别为1.08×10-5A/cm2和7.79×10-6A/cm2。实验结果还表明,HfTiO样品由于Ti元素的引入提高了介电性能,但是Ti的扩散也使得界面态密度升高。     

Anodic Oxidation of Si in Oxygen/Chlorine Plasma

By adding a few percent of chlorine to oxygen plasma, the anodization rate of Si was enhanced; for example, the rate was doubled for oxygen containing 3-percent chlorine. With a chlorine concentration of 1.5 percent, the density of trap states at the Si-SiO/sub 2/ interface was reduced from 7 X 10/sup 11//cm/sup 2//spl dot/eV to 5 X 10/sup 11//cm/sup 2/ /spl dot/eV at the midgap of Si; after annealing at 800/spl deg/C in argon for 60 min, it was reduced to 8 X 10/sup 10//cm/sup 2//spl dot/eV, and did not return to the original value after heating the specimen to 800/spl deg/C. The density and capture cross section of traps in plasma-anodic oxide were also measured using the constant-current avalanche-injection method. The number of electron traps with small cross sections in plasma-anodic SiO/sub 2/ films was reduced by annealing them at 800/spl deg/C in argon, but SiO/sub 2/ films which were anodized in oxygen/chlorine plasma showed an increase of trap density under the same annealing condition.     

GaN基光发射二极管中深能级研究

利用深能级瞬态谱 (DLTS)仪对 Si C衬底上 Ga N基光发射二极管 (LED)中 n-In0 .2 5Ga0 .75N层的深能级进行了研究。在 77K到 3 0 0 K的温度扫描范围内只测量到一个 DLTS峰。该 DLTS峰在反向偏压为 3 V时有一极大值 ,说明 n-In0 .2 5Ga0 .75N层此时全部被耗尽。改变测量的率窗 ,得到该深能级在导带下 0 .2 4e V处 ,浓度为 2 .2 % ND,俘获截面为 1 .93× 1 0 - 1 5cm2。在 Ga N材料中 ,其他小组也报道了此位置上的深能级结果。结合文中的工作 ,该深能级可能和 n-In0 .2 5Ga0 .75N层中的线位错有关。