Semiconductor devices and data storage systems including the same

A semiconductor device, comprising:

• a first substrate structure including
• a substrate,
• a first circuit element and a second circuit element sequentially arranged in the substrate in a first direction perpendicular to an upper surface of the substrate, and
• an element isolation layer in the substrate;
• and
• a second substrate structure on the first substrate structure, the second substrate structure including
• a plate layer,
• gate electrodes spaced apart from each other and stacked in the first direction on a surface of the plate layer, and
• channel structures extending into the gate electrodes in the first direction,
• wherein the substrate includes a first semiconductor region extending into the substrate from the upper surface of the substrate in the first direction and a second semiconductor region extending into the substrate from a lower surface of the substrate in the first direction,
• wherein the first circuit element includes a first gate electrode layer on a side surface of the first semiconductor region, and first source/drain regions respectively in an upper portion and a lower portion of the first semiconductor region,
• wherein the second circuit element includes a second gate electrode layer on a side surface of the second semiconductor region, and second source/drain regions respectively in an upper portion and a lower portion of the second semiconductor region, and
• wherein a first portion of an upper surface of the second semiconductor region is in contact with the first semiconductor region, and a second portion of the upper surface of the second semiconductor region is in contact with the element isolation layer.

A data storage system, comprising:

• a semiconductor storage device including (i) a first substrate structure including a substrate, a first circuit element, and a second circuit element, (ii) a second substrate structure including gate electrodes, and (iii) an input/output pad electrically connected to the first and second circuit elements;
• and
• a controller electrically connected to the semiconductor storage device through the input/output pad and configured to control the semiconductor storage device,
• wherein the first circuit element and the second circuit element are stacked in the substrate in a first direction perpendicular to an upper surface of the substrate, and
• wherein the first substrate structure includes
• a peripheral region insulating layer on the upper surface of the substrate,
• a backside insulating layer on a lower surface of the substrate,
• front contacts electrically connected to the first circuit element by extending into the peripheral region insulating layer,
• backside contacts electrically connected to the second circuit element by extending into the backside insulating layer, and
• a common contact electrically connected to the first circuit element and the second circuit element by extending into the peripheral region insulating layer.