An object is to provide a semiconductor device of which a manufacturing process is not complicated and by which cost can be suppressed, by forming a thin film transistor using an oxide semiconductor film typified by zinc oxide, and a manufacturing method thereof. For the semiconductor device, a gate electrode is formed over a substrate; a gate insulating film is formed covering the gate electrode; an oxide semiconductor film is formed over the gate insulating film; and a first conductive film and a second conductive film are formed over the oxide semiconductor film. The oxide semiconductor film has at least a crystallized region in a channel region.

Semiconductor device, and manufacturing method thereof

Structure and properties of TiN coatings

Reactive-sputter-deposited TiN films on glass substrates

The effects of strain energy on the preferred orientation of TiN thin films were investigated. In the TiN film deposited by plasma‐enhanced chemical‐vapor deposition with a power of 50 W, the overall energy of the film mainly depended on the surface energy because its strain energy was relatively small. The preferred orientation of the film corresponded to the plane with the lowest surface energy, i.e., (200). However, in the TiN film deposited by rf sputtering with a power of 200 W, the overall energy of the film was largely controlled by strain energy due to its large strain energy, and its growth orientation corresponded to the plane with the lowest strain energy, i.e., (111). Furthermore, the preferred orientation of the TiN film was changed from (200) to (111) with the film thickness. It is considered that this phenomenon is due to the increase of strain energy with its thickness.

Effects of strain energy on the preferred orientation of TiN thin films

The mechanical properties of wear-resistant coatings: I: Modelling of hardness behaviour

Mechanisms of reactive sputtering of titanium nitride and titanium carbide II: Morphology and structure

The crystallization of a‐Si in a‐Si (50‐nm) and Au (5‐nm) thin‐film bilayers has been investigated during heat treatment in a transmission electron microscope. When crystallization of a‐Si first begins at 130 °C, the Au‐Si alloy (Au and a precursor phase) reflections observed at lower temperatures vanish, and several new reflections from metastable Au‐Si compounds occur. Dendritically growing islands of poly‐Si are observed after heating at 175 °C. If the samples are held at a constant temperature of 175 °C for 10 min, the poly‐Si islands coalesce. The formation of poly‐Si depends on the diffusion of Au into a‐Si and the formation of metastable Au‐Si compounds, which act as transport phases for both Si and Au. After crystallization Au segregates to the front and back surfaces of the poly‐Si film. The result of this work and earlier diffraction investigations are interpreted in terms of superlattices based on a sublattice. A fundamental body‐centered‐cubic structure with a=5.52 A and composition Au4Si is s...

Crystallization of amorphous silicon during thin-film gold reaction

Mechanisms of reactive sputtering of titanium nitride and titanium carbide III: Influence of substrate bias on composition and structure

Thin‐film structures of amorphous Si/Al/amorphous Si were deposited consecutively without breaking the vacuum. During annealing to 440 K, Al reacts with Si to form a homogeneous compound layer between the two a‐Si layers. This compound has a unique and well‐defined structure, different from both Al and Si although some similarities exist. The Al silicide observed is stable up to 575 K, at which temperature it dissociates when a‐Si crystallizes.

Formation of aluminum silicide between two layers of amorphous silicon

The reactions between a thin metal film of Al or Ag and a layer of amorphous Si have been investigated using transmission electron microscopy and Auger electron spectroscopy. The samples were analyzed after deposition and after different heat treatments. Al and Ag were found to reduce the crystallization temperature of amorphous Si. A crystallization temperature of 325 °C was observed for the Al–Si structure and of 525 °C for the Ag–Si structure. A new phase between Al and Si, which has not previously been reported, has been detected at a temperature of 150 °C. Some evidence for a formation of a metastable phase between Ag and Si during the crystallization process has also been found.

H.T.G. Hentzell

Papers

Mechanisms of reactive sputtering of titanium nitride and titanium carbide II: Morphology and structure

Crystallization of amorphous silicon during thin-film gold reaction

Mechanisms of reactive sputtering of titanium nitride and titanium carbide III: Influence of substrate bias on composition and structure

Formation of aluminum silicide between two layers of amorphous silicon

Metal induced crystallization of amorphous silicon