Transistor structure and methods of formation

A method, comprising:

• forming a first doped region, comprising a first dopant type, in a substrate;
• forming a second doped region, comprising a second dopant type, in the substrate and adjacent to the first doped region;
• forming a first source/drain region, comprising the second dopant type, in the substrate and on the first doped region;
• forming a second source/drain region, comprising the second dopant type, in the substrate and on the second doped region;
• forming a buffer layer over a portion of the second doped region;
• forming a gate oxide layer over a portion of the first doped region, over the buffer layer, and over an extension region of the second doped region;
• forming a gate structure over the gate oxide layer;
• and
• performing one or more etch operations, based on the gate structure, to remove a first portion of the gate oxide layer and to remove a first portion of the buffer layer, wherein a second portion of the gate oxide layer remains under the gate structure, and wherein a second portion of the buffer layer remains under the gate structure.

A method, comprising:

• forming, in a substrate, a first doped region and a second doped region adjacent to the first doped region;
• forming a buffer layer over at least a portion of the second doped region;
• forming a gate oxide layer over the first doped region, over the second doped region, and over the buffer layer;
• forming a gate structure on the gate oxide layer;
• and
• performing one or more etch operations, based on the gate structure, to remove a first portion of the gate oxide layer and to remove a first portion of the buffer layer, wherein a second portion of the gate oxide layer remains under the gate structure, and wherein a second portion of the buffer layer remains under the gate structure.