A stacked capacitor with (Ba/sub x/Sr/sub 1-x/)TiO/sub 3/ for 256M DRAM

Abstract

A high-dielectric-constant material was applied to a practical stacked DRAM capacitor for the first time. A large unit area capacitance (40fF/pm2) and a low leakage current (<10-'A/cm2) have been realized by the combination of a thin (B%Sr-)TiO, film having an equivalent SiO, thickness of 8kand a P O a capacitor electrode. These characteristics show that this storage capacitor is quite promising for 256M DRAM cells.

Time dependent dielectric breakdown of paraelectric barium-strontium-titanate thin film capacitors for memory device applications

“…If a Fowler-Nordheim type current Jϰexp(Ϫ␣/E) is assumed, the lifetime should be extrapolated by a log(t BD ) vs 1/E plot. For BST capacitors, Koyama et al 10 deposited BST films by rf magnetron sputtering and plotted the device failure time versus the applied stress voltage to extrapolate a TDDB lifetime longer than 100 years at 5 V. The film thickness was 100 nm. Fujii et al 11 deposited the BST films by metalorganic deposition ͑MOD͒ and plotted t BD vs 1/E to extrapolate a lifetime of over 100 years at 5 V. The film thickness was 150 nm.…”

“…15 The current-voltage (I -V) characteristics of BST capacitors have been measured by a number of authors. [7][8][9] However, so far there are only a few brief reports on the important reliability issue of time dependent dielectric breakdown [10][11][12] and no detailed discussion on this topic is available. In this work, the time to breakdown (t BD ) due to TDDB is measured and the lifetime is deduced using an extrapolation method previously developed by the authors for ferroelectric lead-zirconate-titanate.…”

Electrical Switching of Magnetization in the Artificial Multiferroic CoFeB/BaTiO3

“…[24] This novel artificial multiferroic system is fully compatible with semiconductor technology, thanks to the availability of industrial processes for growing Ba x Sr 1-x TiO 3 films on Silicon. [25][26][27][28][29][30][31] For CoFeB thickness below 1.3 nm, PMA is stabilized and the magnetic coercive field follows the ferroelectric hysteresis loop, with a maximum variation of 60% induced by full polarization reversal. This is used to demonstrate the magnetically assisted bipolar switching of the magnetization in CoFeB electrodes, requiring a magnetic bias field as low as 10 Oe and voltage pulses compatible with complementary metal-oxide semiconductor (CMOS) electronics.…”

Effect Of RTA On TiN Films As The Barrier Layer for Pt/BST/Pt Capacitors Prepared By RF Magnetron Co-sputter Technique At Low Substrate Temperature

“…The adoption of high dielectric constant materials simplifies the cell structure [1,2] and maintains immunity against soft error [3,4,5]. Therefore, thin barium strontium titanate (BST) film with a high dielectric constant has attracted great attention for practical use in DRAM capacitors.…”