In an embodiment of the present disclosure, a device structure includes a fin structure, a gate on the fin structure, and a source and a drain on the fin structure, where the gate is between the source and the drain. The device structure further includes an insulator layer having a first insulator layer portion adjacent to a sidewall of the source, a second insulator layer portion adjacent to a sidewall of the drain, and a third insulator layer portion therebetween adjacent to a sidewall of the gate, and two or more stressor materials adjacent to the insulator layer. The stressor materials can be tensile or compressively stressed and may strain a channel under the gate.