SOI device having an increasing charge storage capacity of transistor bodies and method for manufacturing the same

An SOI device includes an SOI substrate having a stacked structure including a buried oxide layer and a first silicon layer sequentially stacked on a silicon substrate. The SOI substrate possesses grooves having a depth that extends from an upper surface of the first silicon layer to a partial depth of the buried oxide layer. An insulation layer is formed on the lower surfaces of the grooves and a second silicon layer is formed filling the grooves having the insulation layer formed thereon. Gates are formed on the second silicon layer and junction regions are formed in the first silicon layer on both sides of the gates to contact the insulation layer.