Dielectric constant dependence of Poole-Frenkel potential in tantalum oxide thin films

Wu, Xiaohan; Soss, S.; Rymaszewski, Eugene J.; Lu, T.‐M.

doi:10.1016/0254-0584(94)90205-4

Cited by 34 publications

(19 citation statements)

References 17 publications

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“…18,19,28 The calculated band gap of the a-Ta 2 O 5 , 2.82 eV, is obviously larger than that of the crystalline b-Ta 2 O 5 (0.2 eV) and d-Ta 2 O 5 (1.06 eV) in our calculations. 16 This value for the a-Ta 2 O 5 is about 1.4 eV lower than that of the observed one, 29 which could be attributed to the well-known band-gap underestimation of the local/semi-local approximation of the density functional theory. We have found that the difference of the band gap between a-, b-, and d-Ta 2 O 5 strongly correlates with the distribution of the O-Ta-O bond angles, details of which will be published elsewhere.…”

Section: Resultsmentioning

confidence: 53%

Conduction paths in Cu/amorphous-Ta2O5/Pt atomic switch: First-principles studies

Xiao

Tada

et al. 2014

Journal of Applied Physics

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We have examined the structure of Cu filaments in Cu/amorphous-Ta2O5 (a-Ta2O5)/Pt atomic switch from first principles. We have found that the Cu single atomic chains are unstable during the molecular dynamics (MD) simulation and thus cannot work as conduction paths. On the other hand, Cu nanowires with various diameters are stable and can form conductive paths. In this case, the Cu-Cu bonding mainly contributes to the conductive, delocalized defect state. These make a sharp contrast with the case of single Cu chains in crystalline Ta2O5, which can be conductive paths through the alternant Cu-Ta bonding structure. A series of MD simulations suggest that even Cu nanowires with a diameter of 0.24 nm can work as conduction paths. The calculations of the transport properties of Cu/a-Ta2O5/Pt heterostructures with Cu nanowires between two electrodes further confirm the conductive nature of the Cu nanowires in the a-Ta2O5.

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Section: Resultsmentioning

confidence: 53%

Conduction paths in Cu/amorphous-Ta2O5/Pt atomic switch: First-principles studies

Xiao

Tada

et al. 2014

Journal of Applied Physics

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“…Where C1, C2, and E0 are constants, q is electronic charge, ϕB the barrier height, E is the Dielectric strength is related to the dielectric constant. The Dielectric constant of the inorganic dielectrics is shown in figure 1.5 [31]. It shows that lowest the dielectric constant higher is the field strength of a given dielectric.…”

Section: 111: Resistivitymentioning

confidence: 99%

Investigation on Electrical Properties of RF Sputtered Deposited BCN Thin Films

2013

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The ever increasing advancements in semiconductor technology and continuous scaling of CMOS devices mandate the need for new dielectric materials with low-k values. The interconnect delay can be reduced not only by the resistance of the conductor but also by decreasing the capacitance of dielectric layer. Also cross-talk is a major issue faced by semiconductor industry due to high value of k of the inter-dielectric layer (IDL) in a multilevel wiring scheme in Si ultra large scale integrated circuit (ULSI) devices. In order to reduce the time delay, it is necessary to introduce a wiring metal with low resistivity and a high quality insulating film with a low dielectric constant which leads to a reduction of the wiring capacitance. Boron carbon nitride (BCN) films are prepared by reactive magnetron sputtering from a B4C target and deposited to make metal-insulator-metal (MIM) sandwich structures using aluminum as the top and bottom electrodes. BCN films are deposited at various N2/Ar gas flow ratios, substrate temperatures and process pressures. The electrical characterization of the MIM devices includes capacitance vs. voltage (C-V), current vs voltage, and breakdown voltage characteristics. The above characterizations are performed as a function of deposition parameters. iv To my grandfather late Mr. H Hanumanthaiah and my parents v ACKNOWLEDGMENTS I would like to thank my advisor, Dr. Kalpathy B Sundaram, for his continuous commitment to help and support me through my graduate career. His advice, technical and otherwise, has been valuable to my experience as a graduate student and a s a person. I would also like to thank my committee members, Dr. Jiann S Yuan and Dr. Mingjie Lin, for their support throughout my years at UCF. My heartfelt gratitude goes out to all of my colleagues at the lab-Giji Skaria, Ritika Oswal. Giji was very much instrumental in helping me to perform Vacuum Evaporation experiments and some basic electrical debugging. I would like to thank my father Mr. H Prakash and my mother Mrs. Asha Prakash for their constant motivation and for instilling confidence in me at every step. Also I would like to thank my sister Ms. Ananya Prakash for her love and support. And last but not the least I would like to thank my grandparents and all my relatives and friends who stood by my side during ups and downs of my academic life here.

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“…However, dielectric constants of >35 have also been reported in the literature. 30,31 For example, Wu et al 30 reported that their Ta 2 O 5 films had a dielectric constant in the range of 20-45. Pignolet et al 19 reported that a sample that was subjected to RTA processing in oxygen gas exhibited a dielectric constant of 45, and Lau et al 18 observed that films that were subjected to RTA processing in oxygen gas exhibited a dielectric constant of 40.…”

Section: March 1999mentioning

confidence: 99%

Short‐Duration Rapid‐Thermal‐Annealing Processing of Tantalum Oxide Thin Films

Ezhilvalavan

Tseng

1999

Journal of the American Ceramic Society

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The effect of the rapid thermal annealing (RTA) processing time on the electrical properties of reactively sputtered tantalum oxide (Ta 2 O 5 ) films that was deposited onto Pt/SiO 2 / n-Si substrates, which resulted in the formation of a metalinsulator-metal (MIM) planar capacitor structure, was studied. The Ta 2 O 5 MIM capacitors were subjected to different RTA processing times (30 s to 30 min) at temperatures in the range of 600°-800°C in an ambient oxygen-gas atmosphere. A very-short-duration RTA process at a temperature of 800°C in oxygen gas for 30 s crystallized the films, decreased the leakage current density (to 10 −10 A/cm 2 at a stress field of 100 kV/cm), increased the dielectric constant (to 52), and resulted in the most-reliable timedependent dielectric-breakdown characteristics. The decrease in leakage current density was attributed to the reduction of oxygen vacancies and the suppression of silicon diffusion from the SiO 2 /n-Si substrate into the Ta 2 O 5 grain and the grain boundary, because of the shorterduration annealing. Increasing the annealing time to >30 s increased the leakage current density. The annealing duration of the RTA process was more crucial in regard to obtaining optimum dielectric properties and low leakage current densities. Time-dependent dielectric-breakdown characteristics indicated that Ta 2 O 5 MIM film capacitors that were subjected to an RTA process at a temperature of 800°C for 30 s in oxygen gas can survive a stress field of 1.5 MV/cm for 10 years. The electrical and dielectric measurements in the MIM configuration showed that Ta 2 O 5 is a good dielectric material and is suitable for use in future dynamic random-access memories.

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Dielectric constant dependence of Poole-Frenkel potential in tantalum oxide thin films

Cited by 34 publications

References 17 publications

Conduction paths in Cu/amorphous-Ta2O5/Pt atomic switch: First-principles studies

Conduction paths in Cu/amorphous-Ta2O5/Pt atomic switch: First-principles studies

Investigation on Electrical Properties of RF Sputtered Deposited BCN Thin Films

Short‐Duration Rapid‐Thermal‐Annealing Processing of Tantalum Oxide Thin Films

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