Dopant Activation After Ion Implantation

Dopant activation is the electrically useful fraction of introduced dopant atoms. Implantation places atoms and damages the lattice; later heat can repair damage and move dopants onto electrically active sites. Activation and diffusion are different outcomes and must be checked separately in the selected silicon Flow [T1].

Physics & Mechanism

An implanted atom does not become active simply by being present. Its lattice site and the remaining defects matter. Sheet resistance or carrier measurements probe electrical behavior, while a depth profile describes where the atoms are; neither measurement alone gives the whole answer [T1].

Activation and diffusion share a thermal history

The same thermal history may increase the electrically active fraction and redistribute the dopant profile. The balance depends on the species, starting damage and material. A more active region does not automatically retain its original junction shape [T1].

Implant-related point defects can temporarily accelerate diffusion. The starting crystalline or amorphous state therefore affects how an anneal should be interpreted. A process label alone cannot predict the final active fraction or junction profile [T1].

Follow the selected steps in the public Flow

The 40nm BSI CMOS Image Sensor Flow places VSS and Periphery P-Well Contact IIP before a later Dopants Activation Step; an ashing and clean Step lies between them. The selected trail compares their purposes, not a complete recipe or a direct measurement of activation [T1].

What to check in another device

For another device, identify the dopant and host material, the way it was introduced, the starting damage and later thermal steps. Then compare electrical measurements with the chemical depth profile before claiming that activation was successful [T1].