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Future MIM capacitor generations will require significantly increased specific capacitances by utilization of high-k dielectric materials. In order to achieve high capacitance per chip area, these dielectrics have to be deposited in three-dimensional capacitor structures by ALD or AVD (atomic vapor deposition) process techniques. In this study eight dielectric materials, which can be deposited by these techniques and exhibit the potential to reach k-values of over 50 were identified, prepared and characterized as single films and stacked film systems. To primarily focus on a material comparison, preliminary processes were used for film deposition on planar test devices. Measuring leakage current density versus the dielectric constant k shows that at low voltages (≤1 V) dielectrics with k-values up to 100 satisfy the typical leakage current density specification of <10−7 A/cm2 for MIM capacitors. At higher voltages (3 V) this specification is only fulfilled for dielectrics with k-values below 45. As a consequence, the maximum achievable capacitance gain by introducing high-k dielectrics depends on the operating voltage of the application, such as DRAM capacitors or RF and blocking capacitors. To meet the reliability requirements for RF and blocking capacitors, high-k dielectric film thicknesses of up to 50 nm are necessary.

Nachhaltig Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen TAZ Spiegelau

Patent

R. Berger, H. Gruber, W. Lehnert, Günther Ruhl, R. Foerg, A. Mauder, H.-J. Schulze

Method for manufacturing a composite wafer having a graphite core, and composite wafer having a graphite core

2013

Nachhaltig Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen TAZ Spiegelau

Zeitschriftenartikel

W. Lehnert, Günther Ruhl, A. Gschwandtner

Plasma enhanced atomic layer batch processing of aluminum doped titanium dioxide

Journal of Vacuum Science & Technology A, vol. 30, no. 1

2012

DOI: 10.1116/1.3670876

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Among many promising high-k dielectrics, TiO2 is an interesting candidate because of its relatively high k value of over 40 and its easy integration into existing semiconductor manufacturing schemes. The most critical issues of TiO2 are its low electrical stability and its high leakage current density. However, doping TiO2 with Al has shown to yield significant improvement of layer quality on Ru electrodes [S. K. Kim et al., Adv. Mater. 20, 1429 (2008)]. In this work we investigated if atomic layer deposition (ALD) of Al doped TiO2 is feasible in a batch system. Electrical characterizations were done using common electrode materials like TiN, TaN, or W. Additionally, the effect of plasma enhanced processing in this reactor was studied. For this investigation a production batch ALD furnace has been retrofitted with a plasma source which can be used for post deposition anneals with oxygen radicals as well as for directly plasma enhanced ALD. After evaluation of several Ti precursors a deposition process for AlTiOx with excellent film thickness and composition uniformity was developed. The effects of post deposition anneals, Al2O3 interlayers between electrode and TiO2, Al doping concentration, plasma enhanced deposition and electrode material type on leakage current density are shown. An optimized AlTiOx deposition process on TaN electrodes yields to leakage current density of 5 × 10−7 A/cm2 at 2 V and k values of about 35. Thus, it could be demonstrated that a plasma enhanced batch ALD process for Al doped TiO2 is feasible with acceptable leakage current density on a standard electrode material.

Nachhaltig Angewandte Naturwissenschaften und Wirtschaftsingenieurwesen TAZ Spiegelau

Vortrag

Günther Ruhl, W. Lehnert, C. Wenger

CVD grown ternary high-k oxides for MIM capacitors

Novel High-k Applications Workshop, Dresden

2011

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Suche nach „[W.] [Lehnert]“ hat 12 Publikationen gefunden

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