A method includes bonding a first wafer to a second wafer; after bonding the first wafer to the second wafer, bonding a third wafer to the first wafer; conducting a process control monitor on the first and second wafers via a first electrical pathway that traverses an interface between the first and second wafers; determining whether a charge present at the interface between the first and second wafers.

The present disclosure relates to an image sensor comprising a substrate. A photodetector is in the substrate. A trench is in the substrate and is defined by sidewalls and an upper surface of the substrate. A first isolation layer extends along the sidewalls and the upper surface of the substrate that define the trench. The first isolation layer comprises a first dielectric material. A second isolation layer is over the first isolation layer. The second isolation layer lines the first isolation layer. The second isolation layer comprises a second dielectric material. A third isolation layer is over the second isolation layer. The third isolation layer fills the trench and lines the second isolation layer. The third isolation layer comprises a third material. A ratio of a first thickness of the first isolation layer to a second thickness of the second isolation layer is about 0.17 to 0.38.

An image sensor includes a p-type silicon layer, a silicon layer disposed on the p-type silicon layer, a p-type SiGe layer disposed on the p-type silicon layer, a boron layer disposed on the p-type SiGe layer, and an anti-reflective coating disposed on the boron layer. A trench can be formed in the image sensor such that the boron layer is disposed in the trench.

High quantum efficiency (QE) and highly stable (back-side illuminated (BSI) image sensors are provided. The BSI image sensors include a first substrate and a high doped, ultra-shallow junction (USJ). The first substrate includes a first side and a second side. The first side includes a plurality of image sensor pixels. The second side includes an at least partially exposed epitaxial layer includes a silicon lattice. The USJ is formed in the epitaxial layer. The USJ is formed by applying a dopant to the epitaxial layer utilizing atomic layer deposition (ALD) or monolayer doping (MLD) and laser annealing the epitaxial layer for drive-in diffusion of the dopant into the epitaxial layer and activation of the dopant in the silicon lattice of the epitaxial layer, thereby forming the USJ.

A radiation detector includes, in plan view, a first region including a pixel portion and configured to detect a radiation by the pixel portion including a plurality of pixels, a second region including a plurality of peripheral circuits, and a third region provided between the first region and the second region. A mark portion is disposed in the first region or the third region. The mark portion includes at least one of a first portion and a second portion. The first portion constitutes a surface layer of the radiation detector. The second portion is a portion of a lower layer adjacent to the first portion.