MIM in 3D:dream or reality?

\u3cp\u3eLast decades great effort has been put in the development of 3D capacitors. These capacitors are used for RF decoupling and should therefore have a high capacitance density associated with a sufficient breakdown voltage. Increased capacitance densities have been achieved by exploring the use of the third dimension in silicon, e.g. pores and trenches and considering dielectric layers with a higher dielectric permittivity, so-called higher k dielectrics formed by alternative deposition techniques, e.g. Atomic Layer Deposition (ALD). Starting with the formation of wide pores using the Bosch process, we eventually developed high aspect ratio macropore arrays that have been used as the carrier substrate for the capacitors. These arrays have been filled by conventional LPCVD MOS layers with ONO-dielectrics and in situ doped polycrystalline silicon, initially as single layer stack, but also as a double stack capacitor (MOSOS/MIMIM). Further, higher k materials, such as Al \u3csub\u3e2\u3c/sub\u3eO\u3csub\u3e3\u3c/sub\u3e, Ta\u3csub\u3e2\u3c/sub\u3eO\u3csub\u3e5\u3c/sub\u3e, HfO\u3csub\u3e2\u3c/sub\u3e and even rare earth materials with nanoclusters have been considered in our attempt to achieve ultimate capacitance densities. Our current record capacitance density has been realized using a multiple capacitor structure with ALD electrodes and high k dielectric layers, the so-called MIMIMIM capacitor.\u3c/p\u3

Effect of Central Metal Ion on Molecular Dipole in Porphyrin Self-Assembled Monolayers

The physical and electronic properties of nano-scale semiconductor devices are mainly decided by their surfaces and interfaces. Use of dipolar self-assembled monolayer (SAM) on semiconductor/oxide interfaces has an enormous potential to tailor the behavior of nanoelectronic, optical and biological devices. Among different molecules, porphyrins have been identified to form chemically stable SAMs on different substrates and their dipolar properties can be tuned by incorporating various metal species in them. This allows work-function tuning according to various technological needs. In this paper, we describe the effect of central metal ion (selected period-4 transition metal ions Zn, Cu, Ni, Fe and Co) incorporated in 5-(4-hydroxyphenyl)-10,15,20-tri(p-tolyl)porphyrin (TTPOH) on the surface potential using Kelvin probe microscopy. Density functional theory (DFT) calculations were performed to estimate the magnitude of dipole moments. Also, absorption spectra of TTPOH molecule and its metal derivatives are compared

Cubic phase stabilization and improved dielectric properties of atomic-layer-deposited EryHf1-yOx thin films

The electrical and physical properties of atomic-layer-deposited EryHf1-yOx thin films have been investigated with different stoichiometries of erbium oxide (Er2O3) and hafnium oxide (HfO2). The as-deposited and annealed EryHf1-yOx films exhibit much higher dielectric constants than the reported k-values of the corresponding binary oxides. The highest k-value of 37.6 ± 1 is achieved with 13 at.% of erbium in the film. The enhancement in dielectric constant is due to the formation of the cubic HfO2 phase stabilized by erbium, as revealed by x-ray diffraction experiments. The annealed mixed oxide films exhibit remarkably low oxide charges, low interface states, low leakage, and good breakdown electric fields

Ultrahigh capacitance density for multiple ALD-grown MIM capacitor stacks in 3-D silicon

Trench capacitors containing multiple metal-insulator-metal (MIM) layer stacks are realized by atomic-layer deposition (ALD), yielding an ultrahigh capacitance density of 440 nF/mm2 at a breakdown voltage VBD > 6 V. This capacitance density on silicon is at least 10 times higher than the values reported by other research groups. On a silicon substrate containing high-aspect-ratio macropore arrays, alternating MIM layer stacks comprising high-k Al2O3 dielectrics and TiN electrodes are deposited using optimized ALD processing such that the conductivity of the TiN layers is not attacked. Ozone annealing subsequent to each Al2O3 deposition step yields significant improvement of the dielectric isolation and breakdown properties