Tzu-Chun Yen

Effect of Growth Temperature on Structural Quality of In-Rich Alloys on Si (111) Substrate by RF-MOMBE

In-rich InAlN films were grown directly on Si (111) substrate by RF-MOMBE without any buffer layer. InAlN films were grown at various substrate temperatures in the range of 460–540°C with TMIn/TMAl ~3.3. Structural properties of InAlN ternary alloys were investigated with X-ray diffraction, scanning electron microscopy, and transmission electron microscopy (TEM). It is shown that the deposited In0.8AlM0.2N (0001) films can be in epitaxy with Si (111) substrate with orientation relationship of //. Also, the growth rate around ~0.25 μm/h almost remains constant for growth in the temperature range from 460 to 520°C. Cross-sectional TEM from InAlN grown on Si (111) at 460°C shows that the epitaxial film is in direct contact with Si without any interlayer.

Stability and etching of titanium oxynitride films in hydrogen microwave plasma

Epitaxial titanium oxynitride (TiNO) films deposited on MgO by pulsed laser deposition were treated in hydrogen microwave plasma. Scanning electron microscopy and x-ray photoelectron spectroscopy were used to examine the stability and etching of TiNO which strongly depended on hydrogen gas pressure. TiNO was very chemically stable and remained with good crystallinity under hydrogen pressure below 5300 Pa. With increase of pressure, it may lead to the formation of etch pits in inverse pyramid shape. The etch mechanism as well as the effects of gas pressure and etching time are also presented.

Post sulfurization effect on the MoS2 grown by pulsed laser deposition

Two inches size with high quality layered growth of MoS₂ was achieved by PLD on c-plane sapphire substrate. 2~3 monolayer MoS₂ was obtained within 2 inches wafer estimated from Raman analysis and confirmed by cross-sectional view of TEM. Additionally, the oxide states of Mo 3d core level spectra of MoS₂, analyzed by XPS, can be effectively reduced by adopting a post sulfurization process in H₂S. The post process also improve the photoluminescence (PL) of MoS₂ as well as the electrical characteristic of MoS₂ FET due to elimination the Mo oxide in the grown film.

Defects in nonpolar (13(4)over-bar0) ZnO epitaxial film grown on (114) LaAlO3 substrate

The defects in (134¯0)ZnO epitaxial film grown on (114)LaAlO3 (LAO) have been systematically investigated by using transmission electron microscopy. At the ZnO/LAO interface, the Burgers vectors of misfit dislocations are identified to be 1/3[1¯21¯0] and 1/2[0001]. Threading dislocations with the Burgers vectors of 1/3⟨112¯0⟩ and ⟨0001⟩ are distributed on the basal plane. In (134¯0)ZnO film, the predominant planar defects are basal stacking faults (BSFs) with 1/6⟨202¯3⟩ displacement vectors. The densities of dislocations and BSFs are about 3.8 × 1010 cm−2 and 3.1 × 105 cm−1, respectively.

Defects in nonpolar (134¯0) ZnO epitaxial film grown on (114) LaAlO3 substrate

The defects in (134¯0)ZnO epitaxial film grown on (114)LaAlO3 (LAO) have been systematically investigated by using transmission electron microscopy. At the ZnO/LAO interface, the Burgers vectors of misfit dislocations are identified to be 1/3[1¯21¯0] and 1/2[0001]. Threading dislocations with the Burgers vectors of 1/3⟨112¯0⟩ and ⟨0001⟩ are distributed on the basal plane. In (134¯0)ZnO film, the predominant planar defects are basal stacking faults (BSFs) with 1/6⟨202¯3⟩ displacement vectors. The densities of dislocations and BSFs are about 3.8 × 1010 cm−2 and 3.1 × 105 cm−1, respectively.