Jong-Chang Woo

Low leakage current in metal-insulator-metal capacitors of structural Al2O3/TiO2/Al2O3 dielectrics

Metal–insulator–metal (MIM) capacitors with Al2O3/TiO2/Al2O3 (ATA) dielectrics were fabricated and investigated. At 0 V and frequencies of 100 kHz and 1 MHz, the MIM capacitors with ATA (3/20/3 nm) and ATA (6/20/6 nm) thin films had low leakage current densities of approximately 5.2 × 10−13 and 1.5 × 10−13 A/cm2, respectively, and high capacitance densities of ∼19.48 and ∼20.13 fF/μm2, respectively. The frequency dispersion effect for these MIM capacitors was very small. The electrical transport mechanism, which is the device conduction mechanism, was determined for the varying structures of MIM capacitors.

Dry Etching of Al 2 O 3 Thin Films in O 2 /BCl 3 /Ar Inductively Coupled Plasma

In this study, the etch properties of Al2O3 thin films deposited by atomic layer deposition were investigated as a function of the O2 content in BCl3/Ar inductively coupled plasma. The experiments were performed by comparing the etch rates and selectivity of Al2O3 over the hard mask materials as functions of the input plasma parameters, such as the gas mixing ratio, DC-bias voltage, ratio-frequency (RF) power and process pressure. The highest obtained etch rate was 477 nm/min at an RF power of 700 W, O2 to BCl3/Ar gas ratio of 15%, DC-bias voltage of -100 V and process pressure of 15 mTorr. The deposition occurred on the surfaces when the amount of O2 added to the BCl3/Ar gas was too high at a low DC-bias voltage or high process pressure. X-ray photoelectron spectroscopy was used to investigate the chemical reactions on the etched surface.

Dry-etching properties of TiN for metal/high-k gate stack using BCl3-based inductively coupled plasmaa)

The etch rate of TiN film and the selectivities of TiN∕SiO2 and TiN∕HfO2 were systematically investigated in Cl2∕BCl3∕Ar plasmas as functions of Cl2 flow rate, radio-frequency (rf) power, and direct-current (dc) bias voltage under different substrate temperatures of 10 and 80°C. The etch rate of TiN films increased with increasing Cl2 flow rate, rf power, and dc-bias voltage at a fixed substrate temperature. In addition, the etch rate of TiN films at 80°C were higher than that at 10°C when other plasma parameters were fixed. However, the selectivities of TiN∕SiO2 and TiN∕HfO2 showed different tendencies compared with etch-rate behavior as a function of rf power and dc bias voltage. The relative-volume densities of Ar (750.0nm), Cl (725.2nm), and Cl+ (386.6nm) were monitored with an optical-emission spectroscopy. When rf power increased, the relative-volume densities of all studied particles were increased. X-ray photoelectron spectroscopy was carried out to detect nonvolatile etch by-products from the sur...

Dry etching of CoFe films using a CH4∕Ar inductively coupled plasma for magnetic random access memory application

In this study, the CoFe thin film was studied using an inductively coupled plasma system in CH4-based gas chemistries. The etch rate of the CoFe thin film was systemically studied by the process parameters including the gas mixing ratio, the rf power, the dc-bias power, and the process pressure. The best gas composition for etching was in CH4 (20%)/Ar (80%) ratio. As the rf power and the dc-bias voltage were increased, the etch rate of the CoFe thin film increased in a CH4∕Ar inductively coupled plasma system. The best process pressure condition for etching was 10mTorr in the CH4∕Ar inductively coupled plasma system. The changes in the components on the surface of the CoFe thin film were investigated with energy dispersive x ray.

The periodically negative semi-pyramid nanostructured polymer layer for broadband anti-reflection effect

The periodic negative semi-pyramid nanostructures are fabricated in polymer layer via an imprinting-assisted replication process using the differentially shaped, but periodically textured Si-masters demonstrating the effective reduced reflectance of less than 20% over broadband wavelengths ranging from 300 nm to 1200 nm.

The Dry Etching Properties on TiN Thin Film Using an N 2 /BCl 3 /Ar Inductively Coupled Plasma

In this work, we present a study regarding the etching characteristics on titanium nitride (TiN) thin films using an inductively coupled plasma system. The TiN thin film was etched using a /Ar plasma. The studied etching parameters were the gas mixing ratio, the radio frequency (RF) power, the direct current (DC)-bias voltages, and the process pressures. The baseline conditions were as follows: RF power

The Etching Properties of Al2O3 Thin Films in BCl3/Cl2/Ar Plasma

In this study, the etch mechanism of ALD deposited Al2O3 thin film was investigated in BCl3/Cl2/Ar plasma. The experiments were performed by comparing etch rates and selectivity of Al2O3 over hard mask materials (such as SiO2, and Si3N4) as function of the input plasma parameters such as gas mixing ratio, DC-bias voltage and RF power under fixed process pressure. The maximum etch rate was obtained at 115.75 nm/min under 5 mTorr, RF power 600 W, Cl2 10% was added to BCl3/Ar plasma, and the highest etch selectivity was 1.17 over Si3N4 under the 10 mTorr process pressure, −50 V DC-bias voltage. We used the X-ray photoelectron spectroscopy (XPS) to investigate the chemical reactions on the etched surface.

Etch Properties of Hf-Based High- k Dielectrics Using Inductively Coupled Plasma

In this work, we investigated etching characteristics of HfO 2 thin film and Si using inductive coupled plasma (ICP) system. The maximum etch rate of HfO 2 is 85.5 nm/min at a BCl 3 /(Ar+BCl 3 ) of 20% and decreased with further addition of BCl 3 gas. From the QMS measurements, the most dominant positive ion energy distributions (IEDs) showed a maximum at 20% of BCl 3 . These tendency was very similar to the etch characteristics. This result agreed with the universal energy dependency of ion enhanced chemical etching yields. From the mass spectra, the Hf chloride and bromine oxide must be included in the etching by-products as volatile species.

Dry Etching Characteristics of ZnO Thin Films for the Optoelectronic Device by Using Inductively Coupled Plasma

In this study, we carried out an investigation of the etching characteristics (etch rate, selectivity to ) of ZnO thin films in /Ar inductivity coupled plasma. A maximum etch rate and selectivity of 108.8 nm/min and, 3.21, respectively, was obtained for ZnO thin film at a /Ar gas mixing ratio of 15:16:4 sccm. The plasmas were characterized by optical emission spectroscopy. The x-ray photoelectron spectroscopy analysis showed the efficient destruction of oxide bonds by ion bombardment. An accumulation of low volatile reaction products on the etched surface was also shown. Based on this data, an ion-assisted chemical reaction is proposed as the main etch mechanism for plasmas containing .

The Dry Etching Properties of ZnO Thin Film in Cl 2 /BCl 3 /Ar Plasma

The etching characteristics of zinc oxide (ZnO) were investigated, including the etch rate and the selectivity of ZnO in a /Ar plasma. It was found that the ZnO etch rate, the RF power, and the gas pressure showed non-monotonic behaviors with an increasing Cl2 fraction in the /Ar plasma, a gas mixture of (3 sccm)/(16 sccm)/Ar (4 sccm) resulted in a maximum ZnO etch rate of 53 nm/min and a maximum etch selectivity of 0.89 for ZnO/. We used atomic force microscopy to determine the roughness of the surface. Based on these data, the ion-assisted chemical reaction was proposed as the main etch mechanism for the plasmas. Due to the relatively low volatility of the by-products formed during etching with /Ar plasma, ion bombardment and physical sputtering were required to obtain the high ZnO etch rate. The chemical states of the etched surfaces were investigated using X-ray photoelectron spectroscopy (XPS). This data suggested that the ZnO etch mechanism was due to ion enhanced chemical etching.