Abstract: A diode structure includes a substrate having a first conductivity type, a first well region having a second conductivity type opposite to the first conductivity type and disposed in the substrate, a first doped region having the first conductivity type and disposed in the first well region, a ring-shaped well region having the second conductivity type, disposed in the first well region and surrounding the first doped region, an anode disposed on the first doped region, a second well region having the second conductivity type, separated from the first well region and disposed in the substrate, a second doped region having the second conductivity type and disposed in the second well region, and a cathode disposed on the second doped region.

Abstract: A method for forming a semiconductor structure includes providing a substrate including a first region with a first gate structure and a second region with a second gate structure. First to third dielectric layers are formed on the substrate. The third dielectric layer is patterned to form a first portion in the first region and a second portion in the second region. The second region is covered and at least a portion of the first portion is removed to form a first mask. The second dielectric layer is pattern by using the first mask and the second portion as the second mask to expose a portion of the first dielectric layer. The portion of the first dielectric layer is removed to form a first stacked spacer on the first gate structure and a second stacked spacer on the second gate structure.

Abstract: A method for forming a semiconductor structure includes providing a substrate including a first region with a first gate structure and a second region with a second gate structure. First to third dielectric layers are formed on the substrate. The third dielectric layer is patterned to form a first portion in the first region and a second portion in the second region. The second region is covered and at least a portion of the first portion is removed to form a first mask. The second dielectric layer is pattern by using the first mask and the second portion as the second mask to expose a portion of the first dielectric layer. The portion of the first dielectric layer is removed to form a first stacked spacer on the first gate structure and a second stacked spacer on the second gate structure.