Method of forming a vertical device

A method of forming a vertical device, comprising:

• providing a protrusion over a substrate;
• forming an etch stop layer over the protrusion;
• laterally etching a sidewall of the etch stop layer;
• forming an insulating layer over the etch stop layer;
• forming a film layer over the insulating layer and the etch stop layer with at least one of poly and ashable amorphous carbon film;
• performing chemical mechanical polishing on the film layer and stopping on the etch stop layer;
• etching a portion of the etch stop layer to expose a top surface of the protrusion;
• forming an oxide layer over the protrusion and the film layer;
• and
• performing chemical mechanical polishing on the oxide layer and stopping on the film layer.

A vertical device, comprising:

• a source layer having a protrusion and a base;
• a first layer adjacent to the protrusion;
• a second layer over the base of the source layer and having a larger thickness than the first layer;
• a channel layer over the protrusion of the source layer;
• and
• a drain layer over the channel layer.