Photocurrent spectroscopy of low-k dielectric materials: Barrier heights and trap densities

Atkin, Joanna M.; Song, Daohua; Shaw, T. M.; Cartier, E.; Laibowitz, R. B.; Heinz, Tony F.

doi:10.1063/1.2907958

Cited by 44 publications

(28 citation statements)

References 23 publications

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“…In addition, the barrier height at both the low-k/metal and the low-k/Si interfaces can be measured with internal photoemission experiments. Shamuilia et al 16 and Atkin et al 17 suggest that this value is around 4 eV for both interfaces. This value further proves that the bandgap of most of the SiOCH type low-k dielectrics is similar to that of SiO 2 , indicating that the carbon content in low-k films is not incorporated in the matrix network but primarily exists as terminal methyl groups.…”

Section: Bandgap and Conduction Mechanisms In Low-k Dielectricsmentioning

confidence: 99%

Electrical Reliability Challenges of Advanced Low-k Dielectrics

Baklanov

et al. 2014

ECS J. Solid State Sci. Technol.

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We review the latest studies that address the fundamental understanding of low-k dielectric electrical properties and reliability. We focus on the results discussing the nature of process induced defects, leakage currents and breakdown behavior, as they are important factors to reveal material modification and damage. Issues related to the use of porogen based PECVD techniques during dielectric deposition are discussed, where we focus on the selection of matrix and porogen precursors and on the improvements related to post-deposition treatments. During damascene integration, low-k dielectrics are subjected to several processes that induce material damage, where we review recent learning about plasma exposure, barrier deposition and chemical mechanical polishing. In order to have a successful implementation of advanced ultralow-k films in back-end-of-line interconnects, we argue that more research efforts are needed with respect to its material development, integration and reliability and make some proposals for future work. The development and integration of reliable low-k materials is a key challenge for next generation interconnect technologies. Driven by the requirement of performance increase, highly porous low-k dielectrics are incorporated in deeply scaled back-end-of-line (BEOL) interconnects. In general, there are three important concerns during the study of low-k dielectric electrical properties and reliability: a) the k-value of the dielectric after integration should maintain relatively unchanged, b) the leakage current of the dielectric between metal lines should be low, and c) the time dependent dielectric breakdown (TDDB) failure time of the integrated BEOL structure at operating conditions should meet its specifications. 1Porous SiOCH low-k dielectrics deposited by plasma enhanced chemical vapor deposition (PECVD) techniques are the dominant choice for k>2.2 film depositions and are also potential candidates for ultralow-k (k<2.2) dielectric applications.2 In the past years, significant efforts have been spent to understand their material properties and integration challenges. The bond structures of low-k dielectrics is complex due to the non-equilibrium nature of the PECVD technique.

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Section: Bandgap and Conduction Mechanisms In Low-k Dielectricsmentioning

confidence: 99%

Electrical Reliability Challenges of Advanced Low-k Dielectrics

Baklanov

et al. 2014

ECS J. Solid State Sci. Technol.

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“…4 Previous work on porous low-k materials has demonstrated that plasma exposure can adversely affect the capacitance, breakdown voltage, and leakage currents of these dielectrics, 5,6 and can also significantly reduce time-dependent dielectric breakdown (TDDB) lifetimes. 7 In particular, the slope of the IV characteristics has been found to be related to the Weibull statistics slope of TDDB characteristics in low-k dielectrics.…”

Section: Introductionmentioning

confidence: 99%

The effects of plasma exposure and vacuum ultraviolet irradiation on photopatternable low-k dielectric materials

Nichols

Mavrakakis

Lin

et al. 2013

Journal of Applied Physics

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The effects of plasma exposure and vacuum-ultraviolet (VUV) irradiation on photopatternable low-k (PPLK) dielectric materials are investigated. In order to examine these effects, current-voltage measurements were made on PPLK materials before and after exposure to a variety of inert plasma-exposure conditions. In order to examine the effects of photon irradiation alone, PPLK samples were also exposed to monochromatic synchrotron radiation with 10 eV photon energy. It was found that plasma exposure causes significant degradation in electrical characteristics, resulting in increased leakage-currents and decreased breakdown voltage. X-ray photoelectron spectroscopy measurements also show appreciable carbon loss near the sample surface after plasma exposure. Conversely, VUV exposure was found to increase breakdown voltage and reduce leakage-current magnitudes.

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“…5 During plasma processing, both ion bombardment and vacuum ultraviolet (VUV) irradiation can occur. [6][7][8][9] Defect states (and subsequent trapped charge) generated by both VUV irradiation and charged-particle bombardment of low-k dielectrics have been shown to adversely affect the capacitance, 10-12 breakdown voltage, 13 and leakage currents 14,15 in addition to causing chemical and structural changes 16 in organosilicate dielectrics. In this letter, it is shown that both photons and charged particles emitted during plasma processing have a deleterious effect on the time to dielectric breakdown, i.e., the dielectric lifetime.…”

mentioning

confidence: 99%