FinFET with sloped surface at interface between isolation structures

A device comprising:

• a substrate;
• a first isolation structure over the substrate, the first isolation structure comprising first dopants;
• a second isolation structure over the substrate, the second isolation structure comprising second dopants different from the first dopants;
• a first active fin over the substrate and protruding above a first top surface of the first isolation structure, a first protruding portion of the first active fin having a first height;
• and
• a second active fin over the substrate and protruding above a second top surface of the second isolation structure, a second protruding portion of the second active fin having a second height different from the first height, wherein the first top surface of the first isolation structure and the second top surface of the second isolation structure are sloped at an interface between the first isolation structure and the second isolation structure.

A device comprising:

• a substrate;
• a first isolation structure over the substrate, the first isolation structure comprising p-type dopants;
• a second isolation structure over the substrate, the second isolation structure comprising n-type dopants;
• a first active fin over the substrate and protruding above a first top surface of the first isolation structure, wherein a first acute angle is formed between the first top surface of the first isolation structure and a sidewall of the first active fin;
• and
• a second active fin over the substrate and protruding above a second top surface of the second isolation structure, wherein a second acute angle is formed between the second top surface of the second isolation structure and a sidewall of the second active fin.