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61.
62.
本文提出了一种用于校准流水线模数转换器线性误差的数字后台校准算法。该算法不需要修改转换器级电路部分,只需要一部分用于统计模数转换器输出码的数字电路即可完成。通过分析流水线模数转换器输出的数字码,该算法可以计算出每一级级电路对应的权重。本文利用一个14位的流水线模数转换器来验证该算法。测试结果显示,转换器的积分非线性由90LSB下降到0.8LSB,微分非线性由2LSB下降到0.3LSB;信噪失真比从38dB提高到66.5dB,总谐波失真从-37dB下降到-80dB。转换器的线性度有很大提高。 相似文献
63.
Feng T Xie D Lin Y Zhao H Chen Y Tian H Ren T Li X Li Z Wang K Wu D Zhu H 《Nanoscale》2012,4(6):2130-2133
A single-layer graphene film was grown on copper foil by chemical vapor deposition and transferred onto a silicon-pillar-array (SPA) substrate to make a Schottky junction solar cell. The SPA substrate was specifically designed to suppress reflectance and enhance light absorption. The energy conversion efficiency of the prepared graphene/SPA solar cells achieved a maximum of 2.90% with a junction area of 0.09 cm(2). HNO(3) was employed to dope the graphene in the solar cells, and the time dependence of HNO(3) treatment on the cell performance was studied. Poly(3,4-ethylenedioxythiophene) polystyrenesulfonic acid (PEDOT-PSS) was also introduced in graphene/SPA solar cells by spin coating on top of the graphene film, and its modification on the cell performance was characterized. The results show that both HNO(3) and the PEDOT-PSS film could enhance the energy conversion efficiency of graphene/SPA solar cells. 相似文献
64.
ABSTRACTAluminum nitride is an attractive piezoelectric material for MEMS devices such as bulk acoustic wave (BAW) devices. (002)-oriented AlN films were deposited on Si, Al and Pt by reactive sputtering. Optimized AlN (002) peak reaches a full width at half maximum (FWHM) of 5.6°. Auger electron spectroscopy is used to analyze the oxygen contamination of films. To find the suitable electrode material for device application, the growth mechanism of AlN crystallites on different substrates is also discussed. Based on sputtered AlN films, the prototype of AlN thin film bulk acoustic resonator (TFBAR) was fabricated successfully. 相似文献
65.
Tian-Qi Shao Tian-Ling Ren Chao-Gang Wei Xiao-Ning Wang Chun-Xiao Li Jian-She Liu 《Integrated ferroelectrics》2013,141(1):1241-1248
Fabrication and properties of lead zirconate titanate (PZT) thin films have been studied for Metal-Ferroelectric-Semiconductor FET (MFSFET) devices. PZT based MFS capacitors using lead titanate (PT) as seeding layers have been respectively prepared on p-type ?111? and n-type ?100? silicon wafers directly by a sol-gel method. PZT/PT films are final annealed at 650°C for 1 min in oxygen ambient using rapid thermal annealing (RTA). The measured memory windows of the MFS capacitors are about 1.8 V and 5 V under the polarization voltages of ±5 V and ±10 V correspondingly. The MFS structure can be valuable for MFSFET applications. 相似文献
66.
ABSTRACT A novel structure of piezoelectric acoustic sensors using surface micromachining is proposed and designed. The advantage of surface micromachined acoustic sensors is to reduce the device size while maintaining their good performances compared with bulk micromachined counterparts. The simplified process sequence for the fabrication of acoustic sensors is given and porous silicon is used as a thick sacrificial layer. The PZT-based piezoelectric acoustic sensors exhibit a voltage sensitivity of 61 to 474 μV/Pa, depending on geometry, which ranges from 200 to 500 μm in length of the square membrane. 相似文献
67.
《Diamond and Related Materials》1999,8(10):1891-1894
A computer control system was designed to work with diamond film deposition apparatus to control methane flow automatically. In experiments, the methane flow can fluctuate with a fixed period and fixed amplitude cosine curve. Diamond films were deposited by direct current arc plasma jet and their morphologies were examined by scanning electron microscopy. This proved that the reaction vapor-phase periodic fluctuation had an obvious influence upon the growth and nucleation of diamond. The phenomena of alternate growth and nucleation were observed; especially interesting are the two-dimensional fractal carbon clusters that have been observed for the first time. 相似文献
68.
Based on the Gummel-Poon model of BJT, the change of the DC bias as a function of the AC input signal in RF linear power amplifiers is theoretically derived, so that the linearity of different DC bias circuits can be interpreted and compared. According to the analysis results, a quantitative adaptive DC bias circuit is proposed,which can improve the linearity and efficiency. From the simulation and test results, we draw conclusions on how to improve the design of linear power amplifier. 相似文献
69.
Energy harvesting systems stimulate the development of power management for low power consumption applications. Improving the converter efficiency of power management circuits has become a significant issue in energy harvesting system design. This paper presents a variable step-down conversion ratio switched capacitor (SC) DC-DC converter to advance the converter efficiency of charge on the stored capacitor in a wireless monitoring system of orthopedic implants. The converter is designed to work at 1 MHz switching frequency and achieves 15 to 2 V conversion. Measurement results show that the converter efficiency can reach 42% including all circuit power consumption, which is much higher than previous work. 相似文献
70.
Hole mobility changes under uniaxial and combinational stress in different directions are characterized and analyzed by applying additive mechanical uniaxial stress to bulk Si and SiGe-virtual-substrate-induced strained- Si(s-Si)p-MOSFETs(metal-oxide-semiconductor field-effect transistors)along 110 and 100 channel directions. In bulk Si,a mobility enhancement peak is found under uniaxial compressive strain in the low vertical field.The combination of 100 direction uniaxial tensile strain and substrate-induced biaxial tensile strain provides a higher mobility relative to the 110 direction,opposite to the situation in bulk Si.But the combinational strain experiences a gain loss at high field,which means that uniaxial compressive strain may still be a better choice.The mobility enhancement of SiGe-induced strained p-MOSFETs along the 110 direction under additive uniaxial tension is explained by the competition between biaxial and shear stress. 相似文献