Transistors with a hybrid source or drain

A method of forming a structure for a field-effect transistor, the method comprising:

• forming a first gate structure that extends over a semiconductor fin, wherein the first gate structure has a first side surface and a second side surface opposite the first side surface;
• forming a second gate structure that extends over the semiconductor fin, wherein the second gate structure has a side surface adjacent to the first side surface of the first gate structure;
• forming a first sidewall spacer on the first side surface of the first gate structure;
• forming a second sidewall spacer on the side surface of the second gate structure;
• ion implanting a first portion of the semiconductor fin adjacent to the first side surface of the first gate structure with an ion implantation process to form a first doped region;
• epitaxially growing a first semiconductor layer on the first portion of the semiconductor fin to provide a first source/drain region that includes the first semiconductor layer and the first doped region, wherein the first semiconductor layer is laterally positioned between the first sidewall spacer and the second sidewall spacer, the first semiconductor layer is laterally spaced from the first sidewall spacer by a first distance, and the first semiconductor layer laterally is spaced from the second sidewall spacer by a second distance;
• and
• epitaxially growing a second semiconductor layer in a cavity in the semiconductor fin adjacent to the second side surface of the first gate structure to provide a second source/drain region.