厚膜电阻噪声特性及微调图形对噪声的影响

本文讨论了厚膜电阻器的噪声种类、特性及其产生机理,并提出了减小厚膜电阻器中1/f噪声的途径和方法。文中还讨论了电阻器的微调图形对噪声增量的影响,以及如何减小微调后的噪声增量等。     

厚膜电阻器的噪声及其测量技术

本文论述了厚膜电阻器中噪声的特点、种类和产生机理，重点介绍了厚膜电阻器噪声测量系统和技术以及分析方法。在以上讨论的基础上，分析了厚膜电阻器中的噪声与结构的关系以及低噪声化技术。     

厚膜电阻例行可靠性实验噪声特性研究

厚膜电阻器是混合集成电路中最重要的元件之一。厚膜电阻器以其价格低廉、性能稳定和可靠性高而备受电路设计者的青睐。但是，厚膜电阻器的噪声大是不争的事实。为了能够在精密电路中应用，必须测量和控制电阻器的噪声。近年来，国内外学者发现厚膜电阻器的噪声与厚膜材料结构和质量有密切关系。本文通过厚膜电阻器例行可靠性实验中噪声测量和分析，与常规测量参数对比，探索噪声用于厚膜电阻器例行可靠性实验表征的可行性。     

厚膜电阻器的噪声研究

与金属薄膜电阻器、线绕电阻器不同,厚膜电阻器的结构相当复杂。金属氧化物粗细微粒被埋入玻璃基中。电阻率的大小强烈地依赖于组成成份的百分比。可以认为,决定电阻值大小的主要因素是导电粒子的接触面积,且这些粒子通过隧道效应来传导。 据报道,已研究了一种更易理解的噪声频谱分析法。测量通过样品的交直流电流。我们采用工业用1/3倍频程分析仪,对1.6Hz和25kHz频率范围的输出噪声电压进行了分析。 实验结果表明,厚膜电阻器的玻璃基片将逐步被腐蚀,而噪声的测量与腐蚀的步进次数有关。     

镍铬薄膜电阻器噪声特性研究

薄膜电阻器的低频噪声有别于常规电阻器的噪声特征,与其结构和工艺密切相关。通过溅射工艺生产的阻值为1.5k?镍铬薄膜电阻器分别在生产完成和1000h老化试验之后进行了低频噪声测量和分析得到器件低频噪声特征,结合电子元器件低频噪声理论探讨了器件中各种噪声成分的来源及产生机制并给出该镍铬薄膜电阻生产线降低噪声的工艺手段。并讨论了电迁移损伤对1/f噪声特征的影响,指出噪声的异常波动对电迁移损伤具有明确的指示作用。     

关于激光切割对厚膜电阻噪声特性影响的研究

通过采用激光切割方式来进行模拟定量损伤电阻体,对厚膜电阻器的噪声特性影响进行研究分析,探讨激光切槽长度变化与电阻噪声变化的规律:激光切槽长度在较小阶段时,电阻噪声会随着激光切槽长度的增加而较平缓地上升。但激光切槽长度在较大阶段时,电阻噪声则会随着激光切槽长度的增加而大幅地上升。对此结合了厚膜电阻的微观结构原理进行了分析,确定激光切割引起切槽线周围的厚膜电阻体发生结构性变化,导致厚膜电阻1/f噪声变化为主要因素。     

厚膜片状电阻器及厚膜电阻浆料概述

本文对厚膜电阻器及由它构成的网络电阻器产品，包括性能及生产流程给出了一个简单介绍，着重地对厚膜电阻浆料特别是钌系电阻浆料的组成及性能作了讨论。     

厚膜片式电阻器中的铅

厚膜片式电阻器产品使用的电子浆料包括有：背电极浆料、面电极浆料、电阻浆料、一次玻璃浆料、二次保护浆料、标记浆料、端电极浆料。厚膜片式电阻器产品中的铅全部含在电子浆料中，而在所有膜层中，铅又主要含在电阻体的玻璃粉中。因此，厚膜电阻器产品中的铅适用欧盟豁免条款。 本文从材料成分及产品结构的氟度浅析了厚膜电阻器产品中的铅及如何降低产品中铅的含量。     

厚膜混合集成电路中电阻器的研制

本文主要介绍了厚膜混合集成电路中电阻器的设计、生产、及材料的选择。其中重点介绍了厚膜电阻器材料的主要性能。     

厚膜指数型电阻器特性阻抗的设计

本文主要阐述作为电视差转机端接吸收负载的厚膜指数型电阻器,它不仅能在高频1000MHz下工作,而且其电压驻波比不大于1.22。主要技术指标为直流电阻值,R 50Ω±5%工作频率,f 1GHz交流阻抗,Z_0 50Ω电压驻波比,VSWR≤1.22功率,P 50W对于工作在高频下表现出集中参数的阻抗元件,我们通过用微带设计原理和厚膜工艺技术二者相结合而制作的厚膜指数型电阻器,使得厚膜产品跨出了直流工作的范畴而进入了更为广泛的应用领域。     

Low-frequency noise in thick-film resistors due to two-steptunneling process in insulator layer of elemental MIM cell

In this paper, it is assumed that low-frequency noise source in thick-film resistors are fluctuations of the trap occupations by electrons, tunneling through insulator layer of the elemental cell. Two conducting particles separated by a thin insulating layer form the elemental cell (MIM structure). Trap charge fluctuations are modulating the MIM cell barrier, thus modulating the tunneling current and barrier resistance. A low frequency noise model is proposed under the assumption that the space distribution of traps in thick-film resistor is symmetrical with respect to the central plane of the MIM cell. Numerical results show that in the presence of small number of traps in insulator layer of the elemental cell, 1/f noise is exhibited in a narrow frequency range (4-5 decades). A model is applied on the experimental results for noise in thick-film resistors and a method of evaluation of the trapping state's parameters is discussed based on noise measurements     

Thick-film resistor quality indicator based on noise index measurements

A quality indicator for thick-film resistors based on noise index and resistance measurements is proposed. As this correlates resistor transport and noise characteristics and has mobility dimensions, we titled it to be noise reduced mobility. The experimental results for thick-film resistors, realized using three different resistor compositions with sheet resistances of 1, 10 and 100 kΩ m/sqr show that layers with sheet resistance of 10 kΩ0.25>m/sqr have minimum value of noise reduced mobility in comparison with layers formed using resistor compositions with sheet resistances of 1 and 100 kΩ m/sqr. The potential and resistance distributions measured along test resistors show that the noise reduced mobility is in correlation with thick-film inhomogeneity.     

Low-frequency noise of thick-film resistors as quality and reliability indicator

The non-linearity and the noise of thick-film resistors are parameters that can be used to make a prediction of resistor reliability. The noise spectroscopy measurements of thick-film resistors are proposed as a diagnostic tool for the prediction of possible types of failure. The correlation between noise spectral density data and the results of accelerated aging of thick-film resistors at high temperature were made for HS80 and 2000 resistor pastes.     

High-voltage pulse stressing of thick-film resistors and noise

In this paper the results from a study of high-voltage pulse stressing effects on resistance and low-frequency noise of thick-film resistors based on two different resistor compositions with sheet resistances of 10 and 100 kΩ/sq are presented. For the experimental purposes thick-film test resistors of different dimensions were realized and exhibited to voltage pulses with 1500 and 3000 V amplitudes. Obtained experimental results are qualitatively analyzed from the microstructure, charge transport mechanism and low-frequency noise aspects. Correlation between resistance and low-frequency noise changes with resistor degradation due to high-voltage pulse stressing is observed. It is shown that low-frequency noise is more sensitive to this kind of resistor stressing than resistance and that measured values of noise index are in agreement with resistance noise spectrum results.     

Multiple high-voltage pulse stressing of conventional thick-film resistors

In this paper, results from a study of multiple high-voltage pulse (MHVP) stressing effects on resistance and low-frequency noise of thick-film resistors based on resistor compositions with sheet resistances of 1, 10 and 100 kΩ/sq are presented. For experimental purposes, a series of thick-film test resistors with identical geometries were realized and exhibited to two types of tests: multiple series of 10 pulses with increasing amplitudes from the 0.5 to 4.0 kV range and multiple series of 10 pulses with constant 3 kV and 4.5 kV amplitudes. Obtained experimental results were analyzed and correlation between resistance and low-frequency noise changes with resistor degradation due to MHVP stressing was observed. Comparing the resistance and noise index changes it is shown that low-frequency noise parameters are more sensitive to this kind of resistor stressing than resistance. During high-voltage pulse stressing, certain number of resistors failed and progressive resistor degradation that led to catastrophic failure is also presented in this paper.     

Simultaneous mechanical and electrical straining of conventional thick-film resistors

In this paper results from the study of simultaneous mechanical and electrical straining effects on performances of conventional thick-film resistors based on three different resistor compositions with sheet resistances of 1 kΩ/sq, 10 kΩ/sq and 100 kΩ/sq are presented. For experimental purposes thick-film test resistors of different dimensions were realized. Resistors were simultaneously subjected to mechanical straining with maximal substrate deflection of 300 μm and multiple high-voltage pulses. Obtained experimental results are analyzed from micro- and macrostructural, charge transport and low-frequency noise aspects. Correlations between resistance, gauge factor and low-frequency noise changes with resistor degradation due to simultaneous mechanical and electrical straining are observed.     

Current crowding and its effect on 1/f noise and third harmonic distortion – a case study for quality assessment of resistors

In this paper, we discuss the impact of current crowding on 1/f noise generation and third harmonic distortion in semiconductor devices. We propose a model for the 1/f noise in resistors taking into account the effect of current crowding. This model can be applied to devices that suffer from current crowding due to e.g., multiple spot contacts on homogeneous samples, inter-grain contacts in polysilicon or poly SiGe resistors, grain contacts in thick-film resistors or non-homogeneous thin films and nano particle contacts. The model shows that current crowding has a much larger effect on the 1/f noise of a device than on its resistance.Current crowding at multi-spot contacts also increases the local temperature due to the small value of thermal time constants of multi-spot contacts and increases the contact resistance. This results in third harmonic distortion. Our model explains qualitatively that an increase in 1/f noise goes hand in hand with an increase in third harmonic distortion.     

厚膜电阻的大范围连续可调设计

介绍了厚膜电阻微调系数和大范围连续可调的基本概念,指出常规厚膜电阻微调系数不超过2,采用帽状电阻可以在一定程度上提高微调系数,但由于受到电阻尺寸的限制,仍不能满足10倍以上的大范围连续可调要求。文中探讨了利用串并联微调来设计大范围连续可调电阻的可行性及基本方法。与单个电阻相比,电阻的串并联微调结构对微调系数具有明显的放大作用,从而使大范围连续可调的实现成为可能。当微调系数超过10时,可通过两个帽状电阻的串并联来实现大范围连续可调,三个矩形电阻的串并联结构可使阻值连续可调范围达30倍以上．     

Advanced electrical and stability characterization of untrimmed and variously trimmed thick-film and LTCC resistors

As-fired thick-film resistors have the resistance tolerance within ±20% and this tolerance is increased for smaller components. Therefore the novel trimming methods are necessary for microresistors, especially when they are embedded in LTCC substrate. This paper compares electrical (normalized temperature dependence of resistance, low frequency noise) and stability properties (relative resistance drift, changes of current noise index) of untrimmed, voltage pulse trimmed and laser trimmed unglazed thick-film resistors after step-increased long-term thermal ageing at 162 °C, 207 °C and 253 °C. Moreover the effect of long term exposure (1000 h, 125 °C) and thermal shocks (1000 shocks between −55 °C and 125 °C) is analysed for untrimmed and voltage pulse trimmed buried LTCC resistors.     

Model for the excitation of 1/f noise by high-frequency a.c. signals

A model is presented for the excitation of 1/f noise in carbon and semiconductor resistors by high-frequency a.c. signals. The model does not require special theories on 1/f noise; the observed 1/f noise is attributed, as usual, to resistance fluctuations.