Etch profile control of polysilicon structures of semiconductor devices

A method for forming a semiconductor device, comprising:

• forming a first fin structure on a substrate;
• depositing a first oxide layer on the first fin structure, wherein a first thickness of a first portion of the first oxide layer on a top surface of the first fin structure is greater than a second thickness of a second portion of the first oxide layer on a sidewall of the first fin structure;
• depositing a first gate electrode on the first oxide layer;
• forming a second fin structure on the substrate;
• depositing a second oxide layer on the second fin structure, wherein a first thickness of a first portion of the second oxide layer on a top surface of the second fin structure is substantially equal to a second thickness of a second portion of the second oxide layer on a sidewall of the second fin structure;
• and
• depositing a second gate electrode on the second oxide layer.

A semiconductor device, comprising:

• a first fin field effect transistor (finFET) on a substrate, the first finFET comprising:
• a first fin structure on the substrate;
• and
• a first gate structure comprising a first oxide layer on the first fin structure, a first thickness of a first portion of the first oxide layer on a top surface of the first fin structure being greater than a second thickness of a second portion of the first oxide layer on a sidewall of the first fin structure:
• and
• a second finFET on the substrate, the second finFET comprising:
• a second fin structure on the substrate, and
• a second gate structure comprising a second oxide layer on the second fin structure, a first thickness of a first portion of the second oxide layer on a top surface of the second fin structure being substantially equal to a second thickness of a second portion of the second oxide layer on a sidewall of the second fin structure.