Methods of fabricating metal-oxide-semiconductor transistors having elevated sourcedrain regions are provided. In accordance with the semiconductor memory device and read operation method thereof according to the present invention, one of a plurality of decoding units of a column decoder is selectively operated according to a logic value of one of some of bits of a column address signal. The invention further provides vectors and host cells for the production of the protein and transgenic model systems. The conveyer belt encircles the shafts, and the conveyer belt has a body and multiple second fixing structures, where the fixing structures are arranged in a row on a bottom of the body. The microchip tabs are opposite one another and the cooling device mounting tabs are opposite one another.