Techniques for forming multiple work function nanosheet device

A method of forming a three-dimensional transistor device, comprising;

• performing a first blanket deposition of a P-type work function metal over a P-type nanowire stack and over an N-type nanowire stack, in a complementary metal oxide semiconductor (CMOS) nanosheet device structure, disposed on a substrate;
• directing angled oxygen ions at the CMOS nanosheet device structure, wherein an oxide is formed in the P-type work function metal along a top region of the P-type nanowire stack and the N-type nanowire stack, and wherein an oxide is not formed in the P-type work function metal at a bottom of a trench between the P-type nanowire stack and the P-type nanowire stack;
• and
• performing a vertical etch to remove the P-type work function metal between the P-type nanowire stack and the N-type nanowire stack, while not removing the P-type work function metal above the P-type nanowire stack and the N-type nanowire stack.

A method of forming a three-dimensional transistor device, comprising;

• directing angled oxygen ions at a CMOS nanosheet device structure, comprising a titanium nitride layer disposed over a P-type nanowire stack and over an N-type nanowire stack, wherein titanium oxide is formed in the titanium nitride layer along a top region of the N-type nanowire stack and the P-type nanowire stack, and wherein the titanium oxide is not formed in the titanium nitride layer at a bottom of a trench between the P-type nanowire stack and the P-type nanowire stack;
• performing a first block patterning operation to expose N-type polarity regions in the CMOS nanosheet device structure;
• and
• performing a vertical etch to selectively remove the titanium nitride layer between the P-type nanowire stack and the N-type nanowire stack, wherein the titanium oxide is not removed along the top region.