US Patent 9627511 Vertical transistor having uniform bottom spacers

A method of forming a spacer for a vertical transistor is provided. The method includes forming a fin structure that includes a fin on a semiconductor substrate, forming a source junction or a drain junction at an upper surface of the semiconductor substrate and at a base of the fin and epitaxially growing a rare earth oxide (REO) spacer to have a substantially uniform thickness along respective upper surfaces of the source or drain junction and on opposite sides of the fin structure.