A study of cross-bridge kelvin resistor structures for reliable measurement of low contact resistances (original) (raw)
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IEEE Transactions on Semiconductor Manufacturing, 2000
The parasitic factors that strongly influence the measurement accuracy of Cross-Bridge Kelvin Resistor (CBKR) structures for low specific contact resistances ( c ) have been extensively discussed during last few decades and the minimum of the c value, which could be accurately extracted, was estimated. We fabricated a set of various metal-to-metal CBKR structures with different geometries, i.e., shapes and dimensions, to confirm this limit experimentally and to create a method for contact metal-tometal interface characterization. As a result, a model was developed to account for the actual current flow and a method for reliable c extraction was created. This method allowed to characterize metal-to-metal contact interface. It was found that in the case of ideal metal-to-metal contacts, the measured CBKR contact resistance was determined by the dimensions of the two-metal stack in the area of contact and sheet resistances of the metals used.
IEEE Transactions on Electron Devices, 2000
Various test structures have been employed to determine the specific contact resistivity (ρ c ) of ohmic contacts, and cross Kelvin resistor (CKR) test structures are most suitable for estimating low ρ c values. The value determined by CKRs includes error due to parasitic resistances that have been difficult to account for when ρ c is low (< 10 −7 Ω · cm 2 ). In this paper, an analytical technique for determining the error in measurements from CKR test structures is presented. The analytical model described for circular contacts is based on Bessel function expressions. Using several contacts of different diameter (d) with d/w ≤ 0.4 (w is the width of the CKR arms), the parasitic resistance can be accurately accounted for by extrapolation of experimental data to d/w → 0. Finite-element modeling and experimental results for metal-to-silicide contacts are used to validate the analytical expressions presented.
Accurate contact resistivity extraction on Kelvin structures with upper and lower resistive layers
IEEE Transactions on Electron Devices, 2000
An accurate procedure to extract contact resistivity from contact resistance measurements made on both -resistor and -resistor type Kelvin cross test structures with both upper and lower resistive layers is presented. Through computer simulation it can be shown that the collar effects of both upper and lower layers are additive when both layers have a symmetric geometry. The method is based on the determination of a set of "universal curves" through computer simulation. Using dimensionless variables, these curves can be employed in all experimental conditions, eliminating the need of further simulations.
An Area-Correction Model for Accurate Extraction of Low Specific Contact Resistance
IEEE Transactions on Electron Devices, 2000
The parasitic factors that strongly influence the measurement accuracy of cross-bridge Kelvin resistors have been extensively discussed during the last few decades. The minimum value of specific contact resistance that can be accurately extracted has been estimated. In this paper, we present an analytical model to account for the actual current flow across the contact and propose an area-correction method for a reliable extraction of specific contact resistance. The model is experimentally verified for low-resistivity (close-to-ideal) metal-to-metal contacts. The minimum contact resistance is determined by the dimensions of the two-metal stack in the area of contact and sheet resistances of the metals used.
IEEE Transactions on Electron Devices, 2004
The Cross-Kelvin Resistor test structure is commonly used for the extraction of the specific contact resistance of ohmic contacts. Analysis using this structure are generally based on a two-dimensional model that assumes zero voltage drop in the semiconductor layer in the direction normal to the plane of the contact. This paper uses a three-dimensional (3-D) analysis to show the magnitude of the errors introduced by this assumption, and illustrates the conditions under which a 3-D analysis should be used. This paper presents for the first time 3-D universal error correction curves that account for the vertical voltage drop due to the finite depth of the semiconductor layer.
Specific contact resistivity of AlNiSi contacts using Cross Kelvin Resistor test structure chains
2006
Silicide contacts are used in semiconductor devices because of their relatively low sheet resistance as thin films and because they form contacts with relatively low values of specific contact resistivity leading overall to low values of contact resistance. Determining the true values of the specific contact resistivity of metal-to-silicide interfaces is a challenge that requires suitable test structures. The Cross Kelvin Resistor (CKR) structure is a commonly used test structure for the extraction of the specific contact resistance of ohmic contacts. Analysis using this structure has errors associated with it and the challenge is often in determining this error. This paper demonstrates a technique that uses several Cross Kelvin Resistor structures connected in a chain and determines the specific contact resistance of aluminium to nickel silicide contacts using extrapolation rather than determining the error. The formation of the nickel silicide films and the fabrication and testing results for the Cross Kelvin Resistor structures are presented.
An approach to the low-resistance measurement
Serbian Journal of Electrical Engineering, 2013
The paper presents the real instrument functional characteristics and describes the way of practical solutions of its performance improvement. It presents the design process of the instrument made for resistance measuring. In order to achieve desired objectives, a great number of experiments have been carried out during the development. Basically, the comparison method has been applied. At first, it was intended for the small resistor measuring as a single range unit. Later, the device has been improved and upgraded for a wide range resistance measuring. Finally, some of the difficulties have been detected and explained as well. The paper contains solutions developed and applied for their overcoming.
Methods for Accurate Resistance Measurement
International Journal of Engineering and Advanced Technology
Many devices have components that have very low ohmic properties. The resistances of these components should be measured to ensure their value doesn’t change. An overview is presented on precision resistance measurement for values less than 100Ω. Few techniques like Wheatstone bridge, current-voltage method, current comparators are discussed here.
Specific contact resistivity of Al-NiSi contacts using Cross Kelvin Resistor test structure chains
Microelectronics: Design, Technology, and Packaging II, 2005
Silicide contacts are used in semiconductor devices because of their relatively low sheet resistance as thin films and because they form contacts with relatively low values of specific contact resistivity leading overall to low values of contact resistance. Determining the true values of the specific contact resistivity of metal-to-silicide interfaces is a challenge that requires suitable test structures. The Cross Kelvin Resistor (CKR) structure is a commonly used test structure for the extraction of the specific contact resistance of ohmic contacts. Analysis using this structure has errors associated with it and the challenge is often in determining this error. This paper demonstrates a technique that uses several Cross Kelvin Resistor structures connected in a chain and determines the specific contact resistance of aluminium to nickel silicide contacts using extrapolation rather than determining the error. The formation of the nickel silicide films and the fabrication and testing results for the Cross Kelvin Resistor structures are presented.