Contact resistance

About: Contact resistance is a research topic. Over the lifetime, 15262 publications have been published within this topic receiving 232144 citations. The topic is also known as: electrical contact resistance & ECR.

Development of high conductivity lead (Pb)-free conducting adhesives

Abstract: Electrically conducting adhesive technology is one of the alternatives being actively investigated for the possibility of replacing the solder interconnection technology used for microelectronics applications. An isotropically conducting adhesive consists of metallic filler particles dispersed in the matrix of a polymer resin. Silver-filled epoxy resin is commonly used for thermal conduction in die attach applications. Silver particles can provide electrical and/or thermal conduction, while epoxy provides adhesive bonding of the components to a substrate. This material has several limitations when it is-considered as a replacement for solder interconnections, such as low electrical conductivity, low joint strength, increase in contact resistance upon thermal cycling, lack of reworkability, and silver migration. In order to overcome these limitations, a new formulation is proposed based on alternative Pb-free conducting filler powder and tailored polymer resins. The conducting filler particles are coated with low melting point, non-toxic metals which can be fused to achieve metallurgical bonding between adjacent particles as well as to a substrate. This new conductive adhesive material has shown improved electrical and mechanical properties over the existing silver-filled epoxy materials.

IIIB-8 titanium disilicide contact resistivity and its impact on 1-µm CMOS circuit performance

Abstract: A major feature of modern 1-µm CMOS technology is the use of TiSi 2 -clad diffusions with effective sheet resistances of typically 1 Ω /square. However, until now very little attention has been given to the contact resistance between the TiSi 2 and the underlying diffusions which form the source and drain of the active transistors. Our experimental results have shown that, depending on process conditions, the specific contact resistivity from silicide to n-diffusion varies by six orders of magnitude. In this work it is demonstrated that unless proper care is taken with respect to junction doping concentrations and post-silicide processing to minimize the silicide to diffusion contact resistance, the use of silicided diffusions actually can be detrimental to circuit performance instead of the intended performance enhancement. In this paper we will present: 1) a novel method to evaluate silicide to diffusion contact resistance using only two masks, 2) an outline of the process conditions that yield a minimum contact resistance, 3)circuit simulations showing the impact of this work on circuit performance, and 4) results showing that the modulation of the contact resistance at high current levels can distort the MOS linear region current-voltage characteristics.

Electrographic touch sensor with z-axis capability

Abstract: An electrographic touch sensor having Z-axis capability In one embodiment, a uniform resistive coating is applied to one surface of a substrate and it is within this coating that orthogonal electrical fields are produced using suitable electrodes and voltage applications to give coordinates of a selected position Overlying the resistive coating is a flexible pickoff sheet having a conductive layer facing the combination Interposed between the resistive coating and the conductive layer is an array of a material having a substantially greater resistivity than that of the resistive coating Signals corresponding to the X- and Y-coordinates of a touched point on the sensor are obtained in a substantially conventional manner using an amplifier and an analog to digital converter If desired, a Z-axis component signal due to pressure/force can be obtained in a separate part of the measuring cycle This Z-axis signal is inversely related to a change in the effective contact resistance between the resistive coating and the pick-off sheet caused by the pressure/force The change in this contact resistance is "enhanced" by the high resistance material such that different values of pressure/force can be determined Numerous other embodiments are described including two resistive sheet sensors and enhancing materials that are considered to be insulators

Vibration thresholds for fretting corrosion in electrical connectors

Abstract: Single frequency vibration tests were used to induce fretting corrosion in tin alloy plated contacts. The samples used in this study were connectors consisting of 25 pairs of mated pin and socket contacts. Experimental results for a variety of vibration levels, frequencies, and wiring tie-off lengths are presented. The experiments consisted of running a series of vibration tests at each frequency where the excitation level was stepped through a range of g-levels. During each test run contact resistance was monitored as a performance characteristic. The results exhibit threshold behavior at each frequency for the onset of fretting degradation. Typically a plateau region was observed where similar g-levels produced similar fretting rates. It was also found that outside the plateau region the g-levels varied according to the dynamic behavior of the mechanical system. In addition, a transfer matrix model was used to analyze these results. An empirical fit of the data correlated well with the model when damping was used. This analysis revealed the importance of the bending moment induced at the contact interface as a result of excitation levels and tie-off configurations. Consequently, it is concluded that dynamic response of the mechanical system under various g-levels and tie off configurations can greatly impact the performance of a connector system subjected to vibration stresses.