Silicide resistors for integrated circuits

Thin-film resistors are useful in monolithic integrated circuits whenever high sheet resistance (ρs> 1 kΩ/sq) or radiation hardness are required. Silicide resistive films (MoSi2, CrSi2, and Si-Cr) deposited by dc sputtering have been shown to be compatible with monolithic circuit production end require no protective overlayer. Si-Cr films 200-300 Å thick have ρs, and temperature coefficients of resistance (TCR) ranging from about 1 kΩ/sq and +150 ppm/°C (CrSi2) to 20 kΩ/sq and -1400 ppm/°C (17 at % Cr). MoSi2is best suited for resistor applications requiring 100-200Ω/sq. MoSi2films are about 700 Å thick at 200 Ω/sq, compared to < 100 Å for 200-Ω/sq Ni-Cr, and their TCR is -125 ppm/°C. Typical stability for unprotected silicide resistors in TO-5 packages at 200°C, no load, is < ±3 percent during the first 200 h and < ± 0.5 percent during the next 2000 h. The films are stable during short term exposure to high temperatures as encountered during monolithic or hybrid circuit ceramic package sealing.     

Polycrystalline silicon resistors for integrated circuits

The suitability of thin films of doped polycrystalline silicon on SiO₂ substrates for the production of high value resistors for monolithic integrated circuits is considered. Resistors fabricated from this material posses the advantages of high sheet resistivity and dielectric isolation while still preserving an all silicon technology compatible with conventional production techniques.Relevant structural and electrical properties of doped polycrystalline films produced by both vacuum evaporation onto hot substrates with gas-doping and by diffusion-annealing of amorphous films have been investigated. Sheet resistivities and TCR values measured on 2500 Å polycrystalline films have proved superior to those encountered with conventional diffused resistors. Typically films with sheet resistivities of 1 kΩ/□ had TCR's of ?1000 ppm/°C while conventional diffused resistors are generally made from material of 200 Ω/□ and +2000 ppm/°C TCR. Etched resistor line widths of 0·25 mil. have been obtained in the polycrystalline material employing conventional photolithographic techniques. The temperature stability and linearity of doped polycrystalline resistors have been investigated.     

Precision thin-film cermet resistors for integrated circuits

The use of thin-film resistors in monolithic integrated circuits is becoming more widespread as the performance requirements imposed upon circuit designers become more stringent. A cermet, consisting of a mixture of Cr and SiO, was selected as a suitable resistor mterial for this purpose because of its compatibility with semiconductor materials and processes, and because of its stability and reproducibility over a wide range of sheet resistance. Cermet films with sheet resistances of 300, 1000, and 2000 Ω/square were flash evaporated on silicon substrates, and resistors were fabricated. The techniques for depositing the cermet films and fabricating the resistors are discussed, and methods for subsequently adjusting the resistors to precise values are described. The properties of the completed resistors are presented in detail.     

Large-value monolithic resistors for micropower integrated circuits

The minimum power dissipation of micropower integrated circuits is often limited by the availability of large-value monolithic resistors. Two major types of field-effect resistor structures are examined and an analysis of the primary factors that determine sheet resistance and parasitic capacitance is presented. Resistor tolerance, linearity, and temperature coefficient are briefly discussed. It is shown that resistors with sheet resistances greater than 50 k/spl Omega///spl square/ and parasitic capacitances less than 0.002 pF/k/spl Omega/ can be readily fabricated in a monolithic structure.     

A finite-mesh technique for laser trimming of thin-film resistors

A laser trimming technique in which a finite number of links are cut in a regular mesh of identical-valued resistors is described. The method eliminates long-term resistance drift due to slow annealing in the `heat-affected-zone' adjacent to the laser kerf. It is shown that the precision and resolution can be comparable to those achieved with conventional methods, and that quite wide ranges (up to 4:1) of absolute values can be obtained with small meshes. A computational method for constructing a lookup table of resistor values for different cut patterns is described     

集成化故障检测电路设计

讨论了高频 (微波 )通讯系统中故障检测电路设计的一般方法及设计中应注意的问题 ,并给出了一个设计实例     

Ceramic capacitors for hybrid integrated circuits

Ruggedness, wide capacitance range, high volumetric efficiency, and relatively attractive cost have been the main reasons for the popularity of ceramic chip capacitors. Continuing improvements in most of these categories promise to keep the ceramic chip in its present position of prominence. This article considers multilayer, single-layer, and screened-on configurations. In addition, relationships between size, capacitance, and cost are covered for three common ceramic formulations (NPO, W5R, and Z5U).     

Ar+激光器用于电阻微调的研究

本文讨论并研究了Ar+激光器用于电阻微调的优越性。结果表明,在比常用的Nd:YAG激光功率小得多的情况下,可得到与之相当的刻线宽度和阻值稳定性。     

Techniques of adjusting thin- and thick-film resistors in hybrid microelectronic circuits

Various techniques of adjusting thin- and thick-film resistors in hybrid microelectronic circuits are briefly described and their relative merits and shortcomings pointed out.     

The use of MOS structure for the design of high value resistors in monolithic integrated circuits

The application of P-channel MOS structure as a resistor is studied in detail. The device operates below saturation. Effective sheet resistances of 7-25 kohms/sq. can be achieved with fair controllability. The linearity of the V-I characteristics will be determined by the biasing conditions. The temperature coefficient of such a resistor is ≈0.3-0.35 percent/°C.     

Interconnection systems for solid-state components in hybrid integrated circuits

The factors which can influence the performance and reliability of the interconnection system for solid-state components in hybrid integrated circuits are examined. The main emphasis is on materials that have received most attention in the tantalum film and silicon technologies in the Bell System. However, other materials that are being used are discussed. The interrelation of various factors in choosing an interconnection system is discussed. These factors include the composition of the materials, the methods of depositing various metals, and the properties of the substrates. Among the properties of the materials that are considered, emphasis is laid on environmental stability. The results of environmental tests on conductors and thin-film resistors under high-humidity conditions are reported. Some results on the use of silicone rubber as an encapsulant indicate this material is effective in reducing degradative action on hybrid circuits.     

A compatible technique for the formation of thin tantalum film resistors on silicon integrated circuits

A problem in the production of silicon integrated circuits has been yield limitation and applicability restriction due to the large variation and temperature sensitivity of diffused silicon resistors. Use of a thin-film resistive complement on silicon integrated circuits improves performance of many microcircuits heretofore made by the silicon planar process alone. The technique for thin-film on silicon integrated circuits is based on a two-metal resistor-conductor system: tantalum and aluminum. Tantalum was selected as the resistive material because it can be cathodically sputtered with ease, and a wide range of specific resistivity is available as a result of the controlled energy sputtering technique. The process involves production of the active element part of the circuit with standard silicon integrated circuit planar techniques, including contacting the cuts with deposited aluminum. The only deviation from the standard process lies in leaving some unetched SiO2surface area for resistor deposition. Tantalum is cathodically sputtered over the wafer, and delineated by standard photolithographic techniques to form resistor, conductor, and pad areas. A second layer of aluminum is then vacuum deposited over the wafer, and this is delineated to cover the pad and conductor areas of the tantalum with a high conductivity overlay. The exposed tantalum is then thermally stabilized and the final sheet resistivity adjusted by the resulting controlled sheet resistivity increase. The resulting circuits contain stable resistors with tolerance distributions of ±5 percent to ±10 percent, and TCR of -200 to -300 PPM/°C. The silicon active elements in the circuits do not degrade as a result of the thin-film resistor formation.     

Efficient photodiode-waveguide coupling for hybrid integrated optical circuits

A GalnAsP edge-detecting photodiode was coupled with an SiO2-TiO2 single-mode waveguide in a simple hybrid integration scheme. The newly developed edge-detecting photodiode with a window region was used to improve photodiode durability.     

Quasiplanar 3 dB hybrid for millimetre-wave integrated circuits

A quasiplanar 3 dB hybrid suitable for integration in millimetre-wave fin-line circuits is presented. The performance of the device is characterised by 0.5 dB insertion loss, less than 0.5 dB imbalance and 20?25 dB isolation over the entire Ka-band (26.5?40 GHz).     

n-p-n silicon lateral phototransistors for hybrid integrated optical circuits

An etched mesa silicon lateral phototransistor (EMS-LPT) suitable for detecting the light signal from optical channel waveguides has been designed and fabricated. In this paper both n⁺-p-n⁺uniform base and n⁺-p-p^--n⁺double-diffused EMS-LPT's are reported. The photoactive region of the EMS-LPT is highly localized and can be easily coupled either via an evanescent field or to a grating coupler on a channel waveguide. Light coupling, gain, speed, and signal-to-noise ratio of the device are thereby greatly improved. The fabrication techniques of the EMS-LPT's are compatible with those of MOSFET's, permitting integration of multiple EMS-LPT's and MOSFET load transistors to form optically addressed inverters on the same silicon chip. By flip-chip bonding LiNbO3and silicon substrates and coupling LiNbO3channel waveguides to EMS-LPT's via grating couplers, we produce electrooptic switches with optical input and output.     

Integration of a laser diode with a polymer-based waveguide forphotonic integrated circuits

The fabrication and characterization of BRS lasers monolithically integrated with butt-coupled polymer-based buried strip waveguides is presented. Threshold currents of lasers with one cleaved and one etched mirror facets are 15-18 mA and waveguide output powers are in excess of 5 mW at 100 mA laser driving currents and for 600 μm long waveguides. The device exhibits a total waveguide insertion loss less than 5 dB. The integrated device is potentially suitable as a building-block for photonic integrated circuits     

GaAs/AlGaAs rooftop reflector laser for optoelectronic integrated circuits

A GaAs/AlGaAs laser, consisting of a cleaved facet and a chemically etched total-internal-reflecting rooftop reflector, is fabricated and tested. The results show that the rooftop reflector with the reflectivity exceeding 0.9 can be readily obtained and the laser is suitable for optoelectronic integrated circuits.     

Thermal resistance of VCSELs bonded to integrated circuits

The thermal resistance of vertical-cavity surface-emitting lasers (VCSELs) flip chip bonded to GaAs substrates and CMOS integrated circuits has been measured. The measurements on GaAs show that if the bonding is done properly, the bonding does not add significantly to the thermal resistance. However, the SiO₂ under the CMOS bonding pad can double the thermal resistance unless measures are taken to improve the thermal conductance of these layers. Finite element simulations indicate that the thermal resistance of bonded VCSELs increases rapidly as the solder bond size and the aperture size decrease below ~10 μm     

The application of loss-free resistors in power processing circuits

Applications of loss-free elements with resistive characteristics in power processing systems are discussed. The synthesis of this kind of element is based on the control of a two port which has a transformer or gyrator matrix. Both of the controlled two ports can be realized by means of switched mode circuits. The loss-free resistor can be applied to the stabilization of unstable systems, for damping oscillatory waveforms, and balancing of power flow in AC-DC conversion systems. This kind of element has been applied to the stabilization of a gas laser system. It replaced a conventional resistive element which was applied for this purpose     

集成电路技术发展的物理极限挑战与对策

介绍了集成电路芯片发展的基本规律和现状 ,着重综述了这些规律在微电子学领域所遇到的物理极限挑战及解决这些问题的最新技术 ,并预测了 2 1世纪集成电路技术的重点研究方向