Deok-Sin Kil

Modified atomic layer deposition of RuO2 thin films for capacitor electrodes

The authors investigated the modified atomic layer deposition (ALD) of RuO2 films using bis(ethylcyclopentadienyl)ruthenium [Ru(EtCp)2] at a deposition temperature of 265°C. Oxygen gas diluted with argon was supplied throughout all of the ALD steps. The growth rate of the modified ALD RuO2 was about 1.4A∕cycle, which is higher than that of conventional Ru ALD due to the increase in the amount of Ru(EtCp)2 adsorption per cycle, as well as the difference in the unit cell volumes of Ru and RuO2. The film thickness increased linearly with the number of cycles, and the incubation cycle in the initial stage was negligible.

Effect of nitrogen incorporation on improvement of leakage properties in high-k HfO2 capacitors treated by N2-plasma

The nitrogen incorporation into the HfO2 films with an EOT (equivalent oxide thickness) of 9A was performed by N2-plasma to improve the electrical properties. The dielectric properties and a leakage current characteristics of the capacitors were investigated as a function of plasma power and plasma treatment temperature. The dielectric constant of the capacitors is not influenced by nitrogen incorporation. The N2-plasma treatment at 300°C and 70W exhibits the most effective influence on improvement of the leakage current characteristics. Leakage current density of the capacitors treated at 300°C and 70W exhibits a half order of magnitude lower than that without plasma treatment. Nitrogen incorporated into the HfO2 films possesses the intrinsic effect that drastically reduce the electron leakage current through HfO2 dielectrics by deactivating the VO (oxygen vacancy) related gap states.

Development of New TiN/ZrO2/Al2O3/ZrO2/TiN Capacitors Extendable to 45nm Generation DRAMs Replacing HfO2 Based Dielectrics

New ZrO₂/Al₂O₃/ZrO₂ (ZAZ) dielectric film was theoretically designed and successfully demonstrated to be applicable to 45nm DRAM devices. ZAZ dielectric film is a combined structure from tetragonal ZrO₂ and amorphous Al ₂O₃. Thus prepared ZAZ TFT capacitors showed very small Tox.eq value of 6.3Aring and low leakage current less than 1fA/cell. It was also confirmed that ZAZ TFT capacitor was thermally robust during backend full thermal process by applying it to the final DRAM product in mass production

Leakage Current Characteristics of (Ba,Sr)TiO3 Thin Films Deposited on Ru Electrodes Prepared by Metal Organic Chemical Vapor Deposition

Leakage current characteristics of (Ba,Sr)TiO3 (BST) thin films deposited by metal-organic chemical vapor deposition (MOCVD) on Ru bottom electrodes were investigated. CVD-BST thin film on an Ru electrode showed much higher leakage current density than that on the Pt electrode. In the case of the CVD-BST thin film deposited on the PVD-BST(30 A)/Ru or N2O-plasma-treated Ru electrode, the leakage current density showed a very small value of about 2×10-8 A/cm2 at ±1 V and the dielectric loss was about 0.006. It was found that oxygen atoms adsorbed on the surface of the Ru bottom electrode during the deposition of PVD-BST or N2O plasma treatment played a key role in restoring the barrier height at the bottom interface.

Electrical Properties in High-k HfO2 Capacitors with an Equivalent Oxide Thickness of 9 Å on Ru Metal Electrode

films with an EOT of 9 A were deposited at 300°C on Ru/TiN/ /Si substrates using an atomic layer deposition technique and the electrical properties of Ru//Ru capacitors were investigated as a function of the film thickness and annealing temperature. The dielectric constant, dielectric loss, and leakage current density at 1.0 V in the films with a thickness of 7 nm were , 0.9 %, and , respectively. The capacitors show the stable electrical properties in a thermal treatment up to 600°C.

Complementary logic operation based on electric-field controlled spin–orbit torques

Spintronic devices offer low power consumption, built-in memory, high scalability and reconfigurability, and could therefore provide an alternative to traditional semiconductor-based electronic devices. However, for spintronic devices to be useful in computing, complementary logic operation using spintronic logic gates is likely to be required. Here we report a complementary spin logic device using electric-field controlled spin–orbit torque switching in a heavy metal/ferromagnet/oxide structure. We show that the critical current for spin–orbit-torque-induced switching of perpendicular magnetization can be efficiently modulated by an electric field via the voltage-controlled magnetic anisotropy effect. Moreover, the polarity of the voltage-controlled magnetic anisotropy can be tuned through modification of the oxidation state at the ferromagnet/oxide interface. This allows us to create both n-type and p-type spin logic devices and demonstrate complementary logic operation.Complementary logic devices based on spin–orbit torque can be created in which the tunable polarity of the voltage-controlled magnetic anisotropy effect is used to fabricate n-type and p-type spin logic devices.

Reliability of MIM HAO capacitor for 70nm DRAM

In order to verify the package reliability of a MIM HAO capacitor module, mass production 256M DDR processes with 0.1 /spl mu/m design rule were adopted. The capacitor dielectrics used were HAH and Hf/sub x/Al/sub y/O/sub z/ and showed Tox.eq of 12/spl Aring/ and Lc of<0.2 fA/cell, respectively. With proper thermal compensation for adjusting the cell Vt, we could get a high probe test yield, and high package yield when a MIM HAO capacitor was introduced instead of an SIS Al/sub 2/O/sub 3/ capacitor. With package samples, the refresh time of the device did not degrade after IR and EFR stresses, and finally, we could confirm the reliability of MIM HAO capacitors at package level through long term operation lifetime testing.

EFFECT OF NITROGEN INCORPORATION ON ELECTRICAL PROPERTIES OF HIGH-K NANOMIXED HfxAlyOz FILM CAPACITORS GROWN ON RU METAL ELECTRODES BY ATOMIC LAYER DEPOSITION

ABSTRACT The HfxAlyOz nanomixed capacitors grown by atomic layer deposition were treated by N2-plasma to improve electrical properties. Especially, leakage current characteristics was studied as a function of rf power and treatment temperature. The dielectric constant of the films was not varied irrespective of an increase of rf power and treatment temperature. The leakage current densities of the films treated by N2-plasma were effectively influenced by the treatment temperature rather than rf power. The N2-plasma treatment at 300°C and 70 W exhibits the most effective influence on improvement of the leakage current characteristics. The dielectric constant, dielectric loss, and leakage current density at 2.0 V in 6 nm-thick Hf0.27Al0.24O0.49 nanomixed films treated by N2-plasma at 300°C and 70 W were approximately 16, 0.5%, and 2 × 10− 6 A/cm2, respectively.

Electrical properties of MOCVD BST thin films annealed by rapid thermal annealing process

Abstract The effect of annealing conditions for rapid thermal process on the electrical properties of BST thin films was investigated. RTN annealing was very effective for crystallization, however leakage current property was severely degraded due to the loss of oxygen. RTO annealing after first RTN was very effective to recover the leakage current property, which was severely degraded during prior RTN. BST thin film treated by RTN (700°C) followed by RTO(420°C) showed the very low leakage current density of about 2x 10−8A/cm2 at IV without significant change in dielectric property. Moreover, the underlying TiN barrier was not oxidized at all by those annealing processes.

Investigation on the compositionally graded Hf/sub x/Al/sub y/O/sub z/ films for TiN based DRAM capacitor

New concept of capacitor dielectric thin film was successfully demonstrated through graded Hf/sub x/Al/sub y/O/sub z/ dielectric thin film accompanied by post ozone annealing for the application to DRAM capacitor. MIM capacitor with graded Hf/sub x/Al/sub y/O/sub z/ dielectric films showed drastically reduced leakage current and highly improved breakdown voltage by 0.45-0.75V maintaining the same EOT value. In the case of graded film with Hf/Al=1.5/1, EOT showed very small value of 12.3/spl Aring/ and leakage current could be maintained as low as 1E/sup -16/A/cell at +1.0V.