A new complementary dielectric isolation process for high-voltage devices

A new complementary dielectric isolation process for high-voltage devices has been developed. Both p-type and n-type islands are formed on one chip with a combination of epitaxial growth, anisotropic etching, and some self-alignment techniques. In this technique, the shape, depth, and impurity profile of the islands are precisely controlled, so that the breakdown voltage of more than several hundred volts is easily obtained for the devices formed in the islands.     

A new technology for manufacturing the dielectric isolation of elements of microelectronic devices by oxidizing grooves in single-crystal silicon

The formation of the dielectric isolation of elements of microelectronic devices by oxidizing grooves in single-crystal silicon is considered. The new technological process makes it possible to shorten the manufacturing cycle and to improve the reliability and parameters of devices. It is shown that this result is attained by substantially shortening the time of oxidation of silicon, suppressing the “bird’s beak” irregularity, and reducing the capacitance of the metal-insulator-semiconductor structure through the etching of grooves with certain geometric parameters in silicon nitride. These parameters are the groove width 0.5–1.5 μm, the ratio of the width to the spacing between the grooves 0.56: 0.44, and the groove depth, which is larger than the width. The results of two-dimensional physical simulation support the advantages of the new technology over the standard process. The simulation was accomplished with the use of the SSUPREM4 program of the Silvaco bundled software.     

Microlens fabricated in silicon on insulator using porous silicon

In order to realize the planar gradient refractive index (GRIN) microlens which is based upon porous silicon (PSi) and fabricated on silicon on insulator (SOI), a novel anodization method is used by applying lateral electric field. The microlens with smooth variation of the effective optical thickness is achieved. The lens is transparent in the infrared region, including the optical communication window (1.3 μm<λ<1.6 μm). This approach also allows the fabrication of an array of such lenses on SOI, and the GRIN microlens can be used as potential components in future silicon-based integrated optical circuits.     

Visible photoluminescence of porous silicon covered with an HfON dielectric layer

fect was observed to be greatly weakened for the incorporation of HfON.     

HfOxNy 介质层覆盖的多孔硅可见光致发光

HfOxNy 填充多孔Si空穴结构在室温下得到了改善的光致发光。观测到425nm处强的蓝光和690nm红的发光峰。量子限制效应和极化效应应该是产生发光峰的原因。N/O的化学配比同样影响蓝光发射。最后观测到样品具有极弱的温度淬灭效应。     

Shallow trench isolation based on selective formation of oxidized porous silicon

We have studied the porous silicon (PS) formation dependence on the substrate doping concentration as a selective tool to form locally oxidized regions in silicon wafers. This approach could be used for electrical isolation in CMOS circuits as a promising alternative to the shallow trench isolation STI process which begins to show some limitations (voiding and dishing) for the most advanced technologies.     

一种基于多孔硅光子器件的免标记生物检测法

本文提出了一种免标记、快速便捷、低成本、较 高灵敏度的生物检测的新方法, 其检测原理是通过测量多孔硅中因生物反应引起的折射率的变化来实现对生物分子的检测。 文中采用单层多孔硅样品作为传感器基底,将包虫病(EgP38)抗原链接到多孔硅中,再在 样品上滴加不同浓度的EgP38抗体分子,抗原与抗体发生特异性反应后,采用椭圆偏振仪检 测样品折射率的变化量,通过分析传感器中因发生生物反应而导致的折射率变化量,从而实 现生物检测。该方法首次采用椭圆偏振法实现了对包虫病生物分子的检测,对抗体分子的检 测限为142 nM。     

A mask-free method of patterned porous silicon formation by a localized electrical field

A simple and mask-free method is proposed for the fabrication of p-type patterned porous silicon (PS) using a localized electric field. The electric field is applied by the patterned electrodes (anode and cathode) which are horizontally placed underneath the sample. No masking-layer and related photo-lithography process are needed in this method. Besides, no metal electrodes and hence no metal-pollution in electrolyte have to be concerned in the formation of PS. The morphology of the PS prepared by this method is investigated. Strong visible photoluminescence emissions in the selected areas of PS are demonstrated on PS at about 650 nm.     

Label-free quantitative detection using porous silicon as optical biosensor

The single-layer porous silicon is prepared by electrochemistry etching method,which is used as an immunosensor for determining recombinant mouse zona pellucida 3 fusion protein(r-mZP3) by Raman spectroscopy analysis at room temperature.The molecule binding increases the effective optical thickness(EOT),and thus the Raman spectrum intensity decreases.The concentration and variation of Raman intensity show a good linear quantitative relation.The excellent sensing performance could open the way to a new family of optical sensors for biological standardization.     

A novel method to enhance the gettering efficiency in p-type Czochralski silicon by a sacrificial porous silicon layer

A new two-step phosphorous diffusion gettering(TSPDG) process using a sacrificial porous silicon layer(PSL) is proposed.Due to a decrease in high temperature time,the TSPDG(PSL) process weakens the deterioration in performances of PSL,and increases the capability of impurity clusters to dissolve and diffuse to the gettering regions.By means of the TSPDG(PSL) process under conditions of 900℃/60 min + 700℃/30 min,the effective lifetime of minority carriers in solar-grade(SOG) Si is increased to 14.3 times its original value,and the short-circuit current density of solar cells is improved from 23.5 o 28.7 mA/cm~2,and the open-circuit voltage from 0.534 to 0.596 V along with the transform efficiency from 8.1%to 11.8%,which are much superior to the results achieved by the PDG(PSL) process at 900℃for 90 min.     

利用多孔硅层增强P型CZ硅中吸杂效率的一种新方法

A new two-step phosphorous diffusion gettering(TSPDG) process using a sacrificial porous silicon layer(PSL) is proposed.Due to a decrease in high temperature time,the TSPDG(PSL) process weakens the deterioration in performances of PSL,and increases the capability of impurity clusters to dissolve and diffuse to the gettering regions.By means of the TSPDG(PSL) process under conditions of 900℃/60 min + 700℃/30 min,the effective lifetime of minority carriers in solar-grade(SOG) Si is increased to 14.3 times ...     

A NEW METHOD FOR SOLVING THE SCATTERING PROBLEM OF DIELECTRIC BODIES

A new approach to the EM scattering problem of an inhomogeneous lossy dielectric body is pro-posed.It is shown that the entire interior electric field distribution can be obtained from the measured exteri-or field distribution by simple recurrence relations.Detailed derivations of these recurrence relations for thefield distribution inside the scattering body are presented,and the results obtained by computer simulationsare given.     

Optimised antireflection coatings for planar silicon solar cells using remote PECVD silicon nitride and porous silicon dioxide

Silicon nitride (SiN) films fabricated by remote plasma‐enhanced chemical vapour deposition (RPECVD) have recently been shown to provide an excellent electronic passivation of silicon surfaces. This property, in combination with its large refractive index, makes RPECVD SiN an ideal candidate for a surface‐passivating antireflection coating on silicon solar cells. A major problem of these films, however, is the fact that the extinction coefficient increases with increasing refractive index. Hence, a careful optimisation of RPECVD SiN based antireflection coatings on silicon solar cells must consider the light absorption within the films. Optimal optical performance of silicon solar cells in air is obtained if the RPECVD SiN films are combined with a medium with a refractive index below 1·46, such as porous SiO₂. In this study, the dispersion of the refractive indices and the extinction coefficients of RPECVD SiN, porous SiO₂, and several other relevant materials (MgF₂, TiO_x, ZnS, B270 crown glass, soda lime glass, ethylene vinyl acetate and resin as used in commercial photovoltaic modules) are experimentally determined. Based on these data, the short‐circuit currents of planar silicon solar cells covered by RPECVD SiN and/or porous SiO₂ single‐ and multi‐layer antireflection coatings are numerically maximised for glass‐encapsulated as well as non‐encapsulated operating conditions. The porous SiO₂/RPECVD SiN‐based antireflection coatings optimised for these applications are shown to be universally suited for silicon solar cells, regardless of the internal blue or red response of the cells. Copyright © 1999 John Wiley & Sons, Ltd.     

一种串联RFMEMS开关的隔离度补偿措施

提出了采用陷波电路结构来补偿串联RFMEMS开关断开时的耦合电容,提高其隔离度的一种方法。理论分析显示,采用这种方法,在2～5GHz的频率范围内,可以使开关的隔离度最多提高15郾6dB,而插入损耗只受到0郾07dB的影响。     

Stable InP MIS device using silicon nitride/anodic oxidedouble-layer dielectric

MIS devices are fabricated on InP using a double-layer dielectric consisting of anodic oxide and PECVD silicon nitride. Two different sets of experiments are conducted using tartaric acid and oxalic acid based AGW electrolyte solutions respectively for growing the anodic oxide layer. Devices having the oxalic acid grown anodic oxide layer exhibit capacitance-voltage (C-V) characteristics close to the ideal and are stable for 7200 s under applied bias conditions. The stability of MIS devices is evaluated by determining the accumulation layer charge density versus time     

A new equivalent network method for analyzing discontinuityproperties of open dielectric waveguides

A novel network approach is proposed for analyzing interacting discontinuities on open planar dielectric waveguides by accurately taking account of both surface modes and waves with continuous spectra. In this approach, a continuum of the radiation wave is recomposed into a set of the newly defined spectral composite modes, each of which carries a finite magnitude of radiation power. These new modes, in conjunction with surface modes, construct the complete orthonormal set for expressing an arbitrary local field on a dielectric slab waveguide. This leads to an equivalent network approach effective for solving discontinuity problems, even on an open waveguide using the conventional method for closed-waveguide problems. A number of numerical results are shown to demonstrate the usefulness of the proposed approach     

NH3／H2O2溶液腐蚀下多孔硅光致荧光

用光致荧光谱、傅里叶变换红外光谱（ＦＴＩＲ）和扫描电子显微镜（ＳＥＭ）对用阳极氧化法制成的多孔硅层在１％ＮＨ３／Ｈ２Ｏ２溶液中的腐蚀现象进行了研究。红外分析表明，Ｓｉ－Ｏ键和Ｈ－Ｏ键的强度随ＮＨ３／Ｈ２Ｏ２溶液的腐蚀时间的增加而增加，Ｓｉ－Ｈ键强主匠随腐蚀时间增加而减少。光致荧光谱的峰值在腐蚀开始时先下降后上升，半高宽变窄，谱峰的以边明显蓝移。分析研究表明，１％ＮＨ３／Ｈ２Ｏ２溶液对多孔硅层有腐蚀     

Fabrication of MSM photoconductor on porous Si using micromachined silicon mask

An MSM photoconductive detector has been fabricated from porous silicon using a micromachined silicon mask instead of photolithography. This approach allows damage to porous silicon that can be caused by chemical processing to be avoided. The interdigitated pattern of the silicon mask with a finger spacing of approximately 150 mu m and finger width of 50 mu m was made using silicon micromachining. The fabricated MSM porous silicon photoconductive detector, which exhibits responsivities of better than 0.5 A/W at the wavelength of the He-Ne laser (6280 AA) and a dark current of 950 nA at 10 V, is very promising as an optoelectronic device.<>     

多孔硅的孔隙对硫化锌/多孔硅光电性质的影响

为了研究衬底多孔硅(PS)的孔隙对硫化锌/多孔硅(ZnS/PS)复合体系的光学性能和电学性质的影响,采用脉冲激光沉积方法在不同孔隙度的PS衬底上沉积了硫化锌薄膜。利用X射线衍射仪、扫描电子显微镜、荧光分光光度计和Ⅰ-Ⅴ特性曲线分别研究了PS衬底上ZnS薄膜的晶体结构、表面形貌和ZnS/PS复合体系的光学和电学性质。结果表明,沉积的ZnS薄膜呈立方相晶体结构,沿β-ZnS(111)晶向择优取向生长。随着衬底PS孔隙的增多,ZnS薄膜衍射峰的强度减小,且薄膜表面出现一些空洞和裂缝;在ZnS/PS复合体系的光致发光谱中,PS的发光相对于未沉积ZnS薄膜的PS有所蓝移,随着PS孔隙的增多,该蓝移量增大,而且在光谱中间550nm左右出现了一个新的绿光发射,归因于ZnS的缺陷中心发光。ZnS的蓝、绿光与PS的红光相叠加,整个ZnS/PS复合体系呈现出较强的白光发射。ZnS/PS异质结的Ⅰ-Ⅴ特性曲线呈现出与普通二极管相似的整流特性,在正向偏置下,电流密度较大,电压降较低;在反向偏置下,电流密度接近于0。随着衬底PS孔隙的增多,正向电流增大。该项研究结果为固态白光发射器件的实现奠定了基础。