US Patent 10332963 Uniformity tuning of variable-height features formed in trenches

Methods of forming a structure for a field-effect transistor and related structures. A trench is formed in one or more semiconductor layers, and forming first and second sacrificial sidewall spacers are formed on an upper portion of the trench. A material is formed in the trench that is arranged in part between the first sacrificial sidewall spacer and the second sacrificial space. After forming the material in the trench, the first and second sacrificial sidewall spacers are removed. After removing the first and second sacrificial sidewall spacers, an upper portion of the material is removed with an isotropic etching process.