Abstract: A semiconductor device, includes a channel region, and a source/drain region adjacent to the channel region. The source/drain region includes a first epitaxial layer, a second epitaxial layer epitaxially formed on the first epitaxial layer and a third epitaxial layer epitaxially formed on the second epitaxial layer, and the first epitaxial layer is made of SiAs.

Abstract: A rotating shaft unit includes a first shaft section with a first sleeve adapted to be fixed on the first object, and a second shaft section with a second sleeve fixed on a second object. A fixed plug is secured within the first sleeve. A movable plug is disposed axially and movably within the second sleeve. Each of the fixed and the movable plugs has an integral annular tooth unit. A radial push rod extends movably into the first sleeve and the fixed plug, and is biased to move outward in the first sleeve and the fixed plug. An axial push rod is fixed on the movable plug, extends movable through the fixed plug and the first sleeve, and is biased to an extended position, in which the annular tooth units engage each other to secure relative angular position of the fixed and movable plugs.