Linear and nonlinear characteristics of the silicon CMOS monolithic50-Ω microwave and RF control element

Radio-frequency (RF) control elements using silicon CMOS technology are investigated as an alternative to traditional PIN diode and GaAs MESFET control devices. Silicon CMOS RF control elements are attractive because of their potential in all-silicon monolithic CMOS solutions for completely integrated baseband and RF functions in low-cost wireless systems. Results of the study show that silicon CMOS switches can be designed to rival the insertion loss and isolation of gallium arsenide switches at low frequencies. Data are presented that show less than 1 dB insertion loss and isolation of greater than 50 dB at low frequencies for a variety of silicon CMOS fabrication technologies. A model for a distortion intercept point in MOS switches is presented and validated with experimental measurements     

High-efficiency two lens laser diode to single-mode fiber couplerwith a silicon plano convex lens

A theory for the calculation of the spherical aberration loss of silicon planoconvex lenses is presented. The aberration losses are calculated as a function of the lens parameters. Furthermore, a theory for the coupling efficiency of a laser diode to single-mode fiber for a coupling arrangement consisting of a silicon planoconvex lens and a glass ball lens is given. The theoretical predictions are in good agreement with measurements. Experimentally, a coupling efficiency of 72% (1.4-dB coupling loss) was achieved for a laser diode with farfield angles of 20°×33° FWHM and a not yet fully optimized silicon planoconvex lens     

Photoelectric characteristics of silicon carbide–silicon structures grown by the atomic substitution method in a silicon crystal lattice

Data obtained in an experimental study of the photoelectric characteristics of silicon–silicon carbide structures grown by the atomic substitution method on silicon (100) and (111) substrates are presented. It is found that the maximum sunlight conversion efficiency of a silicon–silicon carbide (silicon carbide–silicon) heterojunction is 5.4%. The theory of dilatation dipole formation upon synthesis by the atomic substitution method is used to account for the mechanism of electrical barrier formation at the silicon–silicon carbide interface.     

Hybrid material integration in silicon photonic integrated circuits

Hybrid integration ofⅢ-Ⅴand ferroelectric materials is being broadly adopted to enhance functionalities in silicon photonic integrated circuits(PICs).Bonding and transfer printing have been the popular approaches for integration of III–V gain media with silicon PICs.Similar approaches are also being considered for ferroelectrics to enable larger RF modulation bandwidths,higher linearity,lower optical loss integrated optical modulators on chip.In this paper,we review existing integration strategies ofⅢ-Ⅴmaterials and present a route towards hybrid integration of bothⅢ-Ⅴand ferroelectrics on the same chip.We show that adiabatic transformation of the optical mode between hybrid ferroelectric and silicon sections enables efficient transfer of optical modal energies for maximum overlap of the optical mode with the ferroelectric media,similar to approaches adopted to maximize optical overlap with the gain section,thereby reducing lasing thresholds for hybridⅢ-Ⅴintegration with silicon PICs.Preliminary designs are presented to enable a foundry compatible hybrid integration route of diverse functionalities on silicon PICs.     

Alternative contact designs for thin epitaxial silicon solar cells

Two major opportunities for increasing the performance of crystalline silicon solar cells involve reducing their thickness and reducing the losses associated with their front metallic grid contacts. Front grid contacted thin epitaxial silicon solar cells based on the growth of crystalline silicon films on a substrate or superstrate have been reported for many years, as have wafer‐based solar cells with alternative contact approaches. Integrating these two concepts into a single device presents an opportunity for simultaneously reducing two major loss mechanisms associated with crystalline silicon solar cells. The opportunities that exist and challenges that must be overcome in order to realize such a device are described in this paper. The design space is defined and explored by considering a wide range of possible approaches. A specific approach was chosen and used to design, grow, and fabricate a proof‐of‐concept thin epitaxial silicon solar cell with an embedded semiconductor grid as an alternative to a conventional front metallic grid. The work presented here has resulted in a thin epitaxial silicon solar cell with a 7·8% designated area conversion efficiency, well isolated contacts, negligible series resistive power loss, and less than 1% shading of the designated area. Copyright © 1999 John Wiley & Sons, Ltd.     

Off-axis properties of silicon and quartz dielectric lens antennas

The theoretical far-field patterns and Gaussian-beam coupling efficiencies are investigated for a double-slot antenna placed off aids on extended hemispherical silicon and quartz lenses. Measured off-axis radiation patterns at 250 GHz agree well with the theory. Results are presented that show important parameters versus off-axis displacement: scan angle, directivity, Gaussicity, and reflection loss. Directivity contour plots are also presented and show that near-diffraction limited performance can be achieved at off-axis positions at nonelliptical extension lengths. Some design rules are discussed for imaging arrays on dielectric lens antennas     

A silicon micromachined four-pole linear phase filter

A 27-GHz four-pole linear phase filter constructed of micromachined cavities in silicon is presented. The structure of the filter consists of four side-by-side horizontally oriented cavities, which are coupled in turn by evanescent waveguide sections with three direct-couplings and one cross-coupling between the first and fourth cavity resonators. The cavities are reduced-height waveguide resonators and are fed by microstrip lines through slot apertures. A time-domain tuning technique is employed to improve the efficiency of the design synthesis. The measured results are presented and compared to those predicted by a finite-element-method model. The simulated filter response has a bandwidth of 2.2% centered at 27.480 GHz with an insertion loss of 1.4 dB at that frequency. The measured performance indicates a 1.9% bandwidth centered at 27.604 GHz with a deembedded insertion loss of 1.6 dB at that frequency and a measured unloaded Q of 1465.     

Double-layered silicon nitride antireflection coatings for multicrystalline silicon solar cells

Silicon nitride coating possesses both optical antireflection and electrical passivation effects for crystalline silicon solar cells. In this work, we employed a double-layered silicon nitride coating consisting of a top layer with a lower refractive index and a bottom layer (contacting the silicon wafer) with a higher refractive index for multicrystalline silicon solar cells. Double-layered silicon nitride coating provides a lower optical reflection and better surface passivation than those of single-layered silicon nitride. Details for optimizing the double-layered silicon nitride coating are presented. In order to get statistical conclusions, we fabricated a large number of multicrystalline silicon solar cells using the production line for both the double-layered and single-layered cell types. It was statistically demonstrated that the double-layered silicon nitride coating provided a consistent enhancement in the photovoltaic performance of multicrystalline silicon solar cells over those of the single-layered silicon nitride coating.     

Characterization of via connections in silicon circuit boards

Conducting vias, isolated by silicon dioxide from a bulk silicon wafer and used to interconnect stripline transmission lines on opposite surfaces of the wafer, are analyzed. The net VSWR (virtual standing wave ratio) and insertion loss for a single via and the crosstalk or coupling between two nearby vias are determined as a function of geometry, frequency, and silicon resistivity. For small via dimensions and frequencies up to 1 GHz, the analysis predicts low VSWR and low insertion loss, provided the silicon resistivity is greater than about 100 Ω-cm. It is shown that crosstalk can be small, and is mostly due to inductive coupling     

Optical study of porous silicon buried waveguides fabricated from p-type silicon

The realisation of optical buried waveguides fabricated from porous silicon layers is presented. The refractive index of porous silicon layer varies according to its porosity and its oxidisation process conditions. So either step or graded index waveguides are achieved. These waveguides are formed by a localised anodisation of heavily doped p-type silicon wafers. Measurements at a wavelength of 1.3 μm yield waveguide losses below 4 dB/cm. The waveguides are also characterised by the near-field-guided mode profile at 1.3 μm. This study deals with the modulation of the waveguiding-layer refractive index and the losses on waveguides fabricated from p⁺.     

集成硅微机械光压力传感器

介绍了一种新颖的集成硅微机械光压力传感器的结构、工作原理、制造工艺和实验结果。该传感器是利用半导体集成电路微细加工技术和各向异性腐蚀相结合的方法，将传输、获取信息的光波导，敏感弹性硅膜和光电探测器集成在一块三维硅基片上得到的。它具有灵敏度高、抗干扰能力强、自身无需电源、防爆、成本低和可靠性高等优点。     

REQUIREMENT OF SILICON FLATNESS FOR SILICON DIRECT BONDING TECHNOLOGY

The influence of silicon slice flatness on bonding technology and the relation between a foreign particle and resulting bubble are quantitatively presented by the elastic theory. It is demonstrated experimentally by X-ray double crystal diffractometry and infrared imager.     

Audiofrequency noise in silicon

Experimental results showing the effects of thermal oxidation and low-temperature annealing in nitrogen on noise-power spectra of single-crystal silicon samples are presented.     

Bulk silicon technology for complementary MESFETs

A technology for fabrication of complementary silicon MESFETs on bulk silicon substrates has been developed. The technology is similar to CMOS technology, and utilises n-silicon substrates. P-wells are used for the n-channel devices. Device isolation was achieved by trench etching. The silicides of Er and Pt were used as gate Schottky contacts. P- and n-channel characteristics are presented together with subthreshold behaviour and preliminary results regarding radiation hardness. Also, results from two-dimensional simulations of the devices are presented.<>     

Characterization of micromachined silicon rectangular waveguide at 400 GHz

We present the first characterization of a micromachined silicon rectangular waveguide at 400GHz. The silicon waveguide has an average loss of 0.086dB/mm for a range of 350-460GHz. The waveguides are formed using well known microfabrication techniques and demonstrate a successful first step towards the use of silicon waveguides as a viable option for THz systems.     

Effects of ionization rates on silicon IMPATT devices

The effects of ionization rates of electrons and holes on the properties of silicon IMPATT devices are presented. Both p-type and n-type silicon diodes are considered. Small- and large-signal results are given for typical X-band devices.     

用于硅衬底隔离的选择性多孔硅厚膜的制备

在硅衬底上形成高阻隔离层对于提高硅基射频电路的性能具有重要意义。采用多孔硅厚膜作为隔离层 ,能够极大地降低衬底高频损耗。本文对n+型硅衬底上选择性多孔硅厚膜的制备进行了研究。通过在阳极氧化反应中采用不同的HF溶液的浓度、电流密度和反应时间来控制多孔硅的膜厚、孔隙度等特性。有效地减少了多孔硅的龟裂失效 ,得到的多孔硅最大膜厚为 72 μm。并测量了多孔硅的生长速率与表面形貌     

Bulk micromachining of silicon

Bulk silicon etching techniques, used to selectively remove silicon from substrates, have been broadly applied in the fabrication of micromachined sensors, actuators, and structures. Despite the more recent emergence of higher resolution, surface-micromachining approaches, the majority of currently shipping silicon sensors are made using bulk etching. Particularly in light of newly introduced dry etching methods compatible with complementary metal-oxide-semiconductors, it is unlikely that bulk micromachining will decrease in popularity in the near future. The available etching methods fall into three categories in terms of the state of the etchant: wet, vapor, and plasma. For each category, the available processes are reviewed and compared in terms of etch results, cost, complexity, process compatibility, and a number of other factors. In addition, several example micromachined structures are presented     

Integrated micromechanical sensors and actuators in silicon

The integrated silicon microsensor and microactuator field is a rapidly developing branch of the microelectronic technology research. The vast potential of these sensors lies in the compatibility with conventional microelectronic circuits in silicon. Special efforts are often required to maintain this fundamental material compatibility, while enabling the fabrication of versatile sensors and actuators. Sensors in silicon are possible for the measurement of many different non-electrical quantities. This overview is focussed on micromechanical sensors and actuators. The basic technologies used for the fabrication of micromechanical structures in silicon are presented with a special emphasis on their compatibility with integrated electronic readout circuits. The performance and the limitations are outlined using several successfully-fabricated integrated sensor and actuator structures.     

Phosphorus doping of silicon by means of neutron irradiation

Phosphorus doping of silicon with the aid of neutron irradiation is a very effective method to produce silicon single crystals with a homogeneous resistivity distribution and an exact average resistivity. The doping process is described and some aspects are given for the handling of the irradiated silicon. Experimental results concerning the resistivity distribution and the accuracy of aim are presented.