Seok-jun Won

Conformal CVD-ruthenium process for MIM capacitor in giga-bit DRAMs

To realize the gigabit-scale DRAM capacitor, it is necessary to develop new electrode materials instead of poly-Si and TiN. Among them, Ruthenium has been the most promising electrode material in advance of Pt or Ir because it can be easily etched by oxygen plasma and shows good electrical properties as a capacitor electrode. But, a CVD-Ru film with good conformality and smooth morphology actually applicable to gigabit-scale DRAM generations has not been known up to now. In this work, we present the development of novel CVD process for application in real device with 3-dimensional structure and the electrical properties of capacitor using CVD-Ru electrode.

Substrate Dependent Growth Rate of Plasma-Enhanced Atomic Layer Deposition of Titanium Oxide Using N2O Gas

TiO 2 thin films were grown on Ru, Pt, Al 2 O 3 -passivated Ru, and Si substrates by plasma-enhanced atomic layer deposition at 280°C. The Ru-substrate-enhanced growth (∼3 times higher than that on Si at <100 cycles) was attributed to the electron donation and the diffusion of previously contained oxygen from Ru onto the growing surface. When the Al 2 O 3 layer was interposed between the Ru substrate and TiO 2 film, even as thin as 0.4 nm, the electron donation was largely suppressed. Above 16―20 nm, the growth rates of rutile TiO 2 (on Ru) and anatase TiO 2 (on Si) were 0.055 and 0.04 nm/cycle, respectively.

Electrical Properties of Crystalline Ta2O5 with Ru Electrode

As one candidate capacitor for dynamic random access memories (DRAMs) of 4 Gbit and beyond, we investigated the electrical properties of Ru/Ta2O5/Ru. In this paper, the dielectric constant of Ta2O5 was measured as a function of annealing temperature and, also, its dependence on film thickness was studied. The effect of postannealing, which was performed after forming a capacitor, on the leakage current of Ru/crystalline-Ta2O5/Ru capacitor was evaluated. Additionally, the leakage current was investigated as a function of Ta2O5 film thickness. Through these experiments, a reliable 7 A Toxeq. of Ta2O5 with a Ru electrode was obtained, which indicates that the Ru/crystalline-Ta2O5/Ru capacitor is a promising candidate for DRAMs of 4 Gbit and beyond.

Mass Production Worthy MIM Capacitor On Gate polysilicon(MIM-COG) Structure using HfO 2 /HfO x C y N z /HfO 2 Dielectric for Analog/RF/Mixed Signal Application

We have successfully integrated a mass production worthy MIM capacitor on gate polysilicon (MIM-COG) structure using HfO₂/HfO_xC_yN_z/HfO₂(HNH) dielectric for the analog/RF/mixed signal application. The insertion of HfO_xC_yN_z into HfO₂ films can successfully suppress the crystallization. As a result, HNH film shows superior breakdown and VCC-a characteristics compared to HfO₂-AI₂O₃ multilayer stack. In addition, we suggest novel MIM-COG structure, which can solve metal routing issues in integration of conventional MIM capacitors. Also, by utilizing the MIM COG structure, the total number of mask can be reduced. Finally, MIM-COG structure with HNH dielectric shows high capacitance density (8.3fF/um²) and low VCC-a (700 ppm/V²). Moreover, excellent operation voltage for 10 year lifetime of MIM-COG structure with HNH (4.6 V) is achieved.

Rugged Metal Electrode (RME) for High Density Memory Devices

Rugged metal electrode (RME) was suggested and evaluated as a bottom electrode of high-density memory capacitors. Rugged ruthenium films (RME-Ru) were successfully fabricated through volume shrinking of ruthenium oxide films under reduction ambient (RuOx+H2=Ru+H2O). The effective surface area of RME-Ru films was significantly enlarged due to the formation of wrinkle on its surface, which resulted in low SiO2 equivalent thickness (Tox) as low as ~ 6 A with Ru/TaOx(110 A)/RME-Ru capacitor. It is believed that RME technique will be very useful to realize and extend MIM (Metal-Insulator-Metal) capacitor era in the mass production of high density memory devices.

High quality high-k MIM capacitor by Ta/sub 2/O/sub 5//HfO/sub 2//Ta/sub 2/O/sub 5/ multi-layered dielectric and NH/sub 3/ plasma interface treatments for mixed-signal/RF applications

Novel high-k MIM capacitor technology for mixed-signal/RF applications has been successfully developed by introducing multilayered high-k dielectric(Ta/sub 2/O/sub 5//HfO/sub 2//Ta/sub 2/O/sub 5/) and NH/sub 3/ plasma electrode-dielectric interfaces treatments. For the first time, we have simultaneously achieved high capacitance of 4fF/um/sup 2/ and low leakage current of 100nA/cm/sup 2/ at high temperature of 125/spl deg/C with ultra low VCC(a=16.9ppm/V/sup 2/, b=5.2ppm/V) and high Q(/spl sim/107 at 2.4GHz and 5.4pF).

High resolution short defect localization in advanced FinFET device using EBAC and EBIRCh

Defect localization of short failures has been a big challenge in modern advanced nanoscale devices. In recent years, Electron Beam Induced Resistance Change (EBIRCh) technique has been applied to failure analysis. The EBIRCh technique incorporated into SEM based nanoprobing system allows not only direct electrical characterization of suspicious bridge sites but also direct pinpointing of short defects with SEM resolution. In this paper, we directly measure electron beam induced current variations with nanoprober for comprehensive understanding of EBIRCh mechanisms. A failure analysis case study will be presented using EBAC and EBIRCh. In an advanced FinFET device, pinpointing of a single fln within 50 nm enabled direct TEM cross-sectioning for invisible defects in plane-view inspections.

Development of the conical spring linear vibrator (CSLV) for mobile phone

In this paper, we proposed a coin shaped linear vibrator having a conical spring. The design of linear vibrator is simple rather than rotary vibrator, which leads to lower cost, easy manufacturing and long lifetime. To increase the vibration force of linear vibrator, we used conical spring. This paper details design procedure of the conical spring linear vibrator (CSLV) using electromagnetic field simulation, structural FE simulation and transient vibration analysis.

Novel plasma enhanced atomic layer deposition technology for high-k capacitor with EOT of 8 /spl Aring/ on conventional metal electrode

We have developed a plasma enhanced atomic layer deposition(PEALD) technology for high-k dielectrics such as Al/sub 2/O/sub 3/,Ta/sub 2/O/sub 5/ and HfO/sub 2/. Film quality and throughput of PEALD are far superior to that of ALD which has been spotlighted as a deposition technology for next generation semiconductor devices. We have obtained a extremely low equivalent oxide thickness(EOT) of 8 /spl Aring/ from HfO/sub 2/ film, which has not been reported in conventional metal-based memory capacitors up to now. It was confirmed that PEALD-Al/sub 2/O/sub 3/ and Ta/sub 2/O/sub 5/ films are superior to those using any other deposition techniques and very useful as System-on-Chip(SoC) capacitors.

Development of CVD-Ru/Ta/sub 2/O/sub 5//CVD-Ru capacitor with concave structure for multigigabit-scale DRAM generation

RIR(Ru/Crystalline-Ta/sub 2/O/sub 5/Ru) capacitor with concave structure was studied for the application into multigigabit-scale DRAM device. In this work, several novel technologies were successfully developed to solve current issues in the fabrication of RIR concave capacitor; such as 1) two-step deposition of Ta/sub 2/O/sub 5/ films 2) formation of Ta/sub 2/O/sub 5/ spacer 3) new separation process of Ru storage node using maskless etch-back method 4) H/sub 2/ pre-annealing and 5) Ar plasma pre-treatment on Ru bottom electrode. The RIR concave capacitor (design rule/spl sim/0.12 /spl mu/m, node height/spl sim/0.85 /spl mu/m) fabricated with these novel technologies showed excellent electrical properties (25fF/cell, 1fA/cell at /spl plusmn/ 1V), which indicates that RIR structure is the one of the most promising candidate for the next generation DRAM capacitor.