Semiconductor device and method for manufacturing the same

A semiconductor device including:

• a plurality of bottom epitaxial layers;
• a plurality of vertical channels formed respectively on the plurality of bottom epitaxial layers;
• a plurality of top epitaxial layers formed respectively on the plurality of vertical channels;
• an insulating spacer extending along sidewalls of the plurality of the vertical channels and upper surfaces of the plurality of the bottom epitaxial layers;
• an insulating layer disposed between adjacent vertical channels, and disposed on the insulating spacer;
• and
• a gate dielectric layer and a gate metal between the plurality of vertical channels and the insulating spacer,
• wherein the plurality of top epitaxial layers is separated by and in direct physical contact with the insulating layer, and an upper surface of the insulating layer is higher than upper surfaces of the plurality of vertical channels, and
• wherein a portion of the insulating layer fills a recess defined by the insulating spacer between adjacent vertical channels.