Patent ID: 9530665
Filing Date: 2016-12-27
CPC Classification: H01L

Claim Text:
1. A method for forming a field effect transistor device, the method comprising: forming a first semiconductor fin and a second semiconductor fin adjacent to the first semiconductor fin on a semiconductor substrate, the second semiconductor fin separated from the first semiconductor fin by a trench region having at least three sidewalls, wherein opposite facing sidewalls of the first semiconductor fin and the second semiconductor fin define first and second sidewalls of the trench region; arranging a gate stack over the first semiconductor fin and over the second semiconductor fin, wherein a first sidewall of the gate stack adjacent to the trench region defines a third sidewall of the trench region; depositing a protective layer on a top surface of the field effect transistor device, wherein the protective layer covers some or all of the top surface; and removing a portion of the protective layer from the top surface of the field effect transistor device using an angled etching process, such that the protective layer remains only along at least the first sidewall of the gate stack and only on a bottom portion of the trench region in direct contact with the semiconductor substrate, wherein the protective layer along the first sidewall of the gate stack defines a gate spacer; wherein the removing the portion of the protective layer comprises: directing a first ion beam generated by an ion beam source at the semiconductor substrate from a first direction at a first oblique angle, wherein the first oblique angle is measured clockwise from a vertical first axis extending perpendicular from a surface of the substrate to a second axis extending perpendicular from an emission point of the ion beam source, and wherein the first ion beam is perpendicular to a long axis of the first semiconductor fin and further comprising: directing a second ion beam generated by the ion beam source at the semiconductor substrate from a second direction counterclockwise to the first direction at a second oblique angle, wherein the second oblique angle is measured from the vertical first axis extending perpendicular from the surface of the substrate to the second axis extending perpendicular from the emission point of the ion beam source, and wherein the second ion beam is perpendicular to the long axis of the first semiconductor fin.