Abstract: A copolyester is formed by copolymerizing a depolymerized polyester and succinic acid. The depolymerized polyester includes depolymerized polyethylene terephthalate (PET), and the depolymerized PET is formed by depolymerizing PET with ethylene glycol. The repeating unit of PET and the succinic acid have a molar ratio of 40:60 to 50:50. The repeating unit of PET and the ethylene glycol have a molar ratio of 100:100 to 100:500. The copolyester has a storage modulus of 1*104 Pa to 1*106 Pa at 80° C. The copolyester can be used in a hot melt adhesive.

Abstract: A semiconductor device includes a substrate and a gate structure. The gate structure is disposed on the substrate, and the gate structure includes a titanium nitride barrier layer a titanium aluminide layer, and a middle layer. The titanium aluminide layer is disposed on the titanium nitride barrier layer, and the middle layer is disposed between the titanium aluminide layer and the titanium nitride barrier layer. The middle layer is directly connected with the titanium aluminide layer and the titanium nitride barrier layer, and the middle layer includes titanium and nitrogen. A concentration of nitrogen in the middle layer is gradually decreased in a vertical direction towards an interface between the middle layer and the titanium aluminide layer.

Abstract: A semiconductor device includes a substrate and a gate structure. The gate structure is disposed on the substrate, and the gate structure includes a titanium nitride barrier layer a titanium aluminide layer, and a middle layer. The titanium aluminide layer is disposed on the titanium nitride barrier layer, and the middle layer is disposed between the titanium aluminide layer and the titanium nitride barrier layer. The middle layer is directly connected with the titanium aluminide layer and the titanium nitride barrier layer, and the middle layer includes titanium and nitrogen. A concentration of nitrogen in the middle layer is gradually decreased in a vertical direction towards an interface between the middle layer and the titanium aluminide layer.

Abstract: A semiconductor device includes a substrate and a gate structure. The gate structure is disposed on the substrate, and the gate structure includes a titanium nitride barrier layer and a titanium aluminide layer. The titanium aluminide layer is disposed on the titanium nitride barrier layer, and a thickness of the titanium aluminide layer ranges from twice a thickness of the titanium nitride barrier layer to three times the thickness of the titanium nitride barrier layer.

Abstract: A semiconductor device includes a substrate and a gate structure. The gate structure is disposed on the substrate, and the gate structure includes a titanium nitride barrier layer and a titanium aluminide layer. The titanium aluminide layer is disposed on the titanium nitride barrier layer, and a thickness of the titanium aluminide layer ranges from twice a thickness of the titanium nitride barrier layer to three times the thickness of the titanium nitride barrier layer.