Jin Hyung Jun

Effect of Structural Properties on Electrical Properties of Lanthanum Oxide Thin Film as a Gate Dielectric

The electrical properties of lanthanum oxide was grown by using metal organic chemical vapor deposition (MOCVD) were investigated from the change of structural properties which occurred during the post-annealing process. The as-grown film had a dielectric constant of 18.8, and capacitance equivalent oxide thickness of 1.7 nm. The leakage current density of the film was measured as 2.4×10-4 A/cm2 at -1 MV/cm. When the film was annealed at 900°C, the dielectric constant decreased with the increase of the interfacial layer.

Properties of Lanthanum Aluminate Thin Film Deposited by MOCVD

The electrical and structural properties of lanthanum aluminate (LAO) thin films, which were deposited by metallorganic chemical vapor deposition (MOCVD) method, were investigated and compared with those of lanthanum oxide (La 2 O 3 ) thin films. The LAO films showed better thermal stability and leakage current density characteristic than La 2 O 3 films. The equivalent oxide thicknesss of LAO film was larger than that of as-deposited La 2 O 3 film and smaller for 900°C annealed film than La 2 O 3 film. It is thought that the LAO film is a promising material which can be used as a high-k gate dielectric in future devices.

A Study on the Crystallization Behavior of Nitrogen Doped Ge2Sb2Te5 Thin Film

We investigated the crystallization behaviors of nitrogen doped Ge2Sb2Te5 thin films deposited in various nitrogen gas flow rates by means of the 4-point probe technique, X-ray diffraction and transmission electron microscopy (TEM), and we mapped the change of crystallization behavior on annealing temperatures. Nitrogen doping resulted in an increase of crystallization temperature from amorphous to fcc structure and maintained the fcc structure up to a higher annealing temperature than un-doped film did. However, crystallization behavior in heavily nitrogen-doped film occurred from an amorphous directly to a hexagonal state, skipping the fcc crystallization step.

A Study on the Lanthanum Aluminate Thin Film as a Gate Dielectric Material

The lanthanum aluminate (LAO) films with three kinds of Al2O3 compositions were deposited by metal-organic chemical vapor deposition (MOCVD) method. The electrical and structural properties of the LAO thin films were investigated and compared with those of each other films. The LAO films had flat surfaces for all deposition and annealing conditions. With the changes of the film composition, the LAO films showed various properties such as the dielectric constant and the thickness of interfacial layer. It is thought that the LAO film with specific composition has a possibility to be used as a high-k gate dielectric in future devices.

LaO x Thin Film Deposited by Direct Liquid Injection MOCVD

The properties of LaO x thin films, which were deposited by direct liquid injection metallorganic chemical vapor deposition, were investigated. For LaO x thin film deposited using 50 sccm oxygen gas flow rate, dielectric constant and leakage current density were 15.6 and 5.4 X 10 - 3 A/cm 2 at -1 V. respectively, and flatband voltage was shifted from -0.12 to 0.10 V with increasing annealing temperature. The results show that the properties of LaO x thin film deposited using 50 seem oxygen gas flow rate are better than the properties of the other LaO thin films deposited using 30 or 100 sccm Oxygen gas flow rate.

Electrical Switching Characteristics of Nitrogen Doped Ge2Sb2Te5 Based Phase Change Random Access Memory Cell

Ge2Sb2Te5 (GST) has been widely studied for PRAM as reversible phase change material. GST is expected to reduce RESET (crystalline → amorphous) operation power, which is one of important issues for PRAM technology. In order to investigate the effect of nitrogen doping on electrical switching characteristics, we fabricated two kinds of PRAM cells with nitrogen-doped (N-doped) and un-doped GST, which were different bottom electrode contact size (0.80~1.00 ). N-doped GST PRAM cells have higher dynamic resistance with small sized bottom electrode contact and lower RESET voltage (about 1.2 V, 50 ns) than un-doped GST PRAM cells (about 1.6 V, 50 ns). The resistance switching ratio (RRESET to RSET) was about 100. The results of this study indicate that nitrogen doping into GST film and smaller size of bottom electrode contact reduce RESET power for PRAM operation.