High concentration doping in semi-conductors is achieved through an In-Situ deposition method which avoids the lattice damage of many external methods by incorporating dopants during crystal growth and proceeding only up to the solubility limit for a given dopant.
- Optical, electrical, or electro-optical devices (HFETs, LD, and LEDs)
- Germanium light emitters
Some doping methods such as ion implantation, severely damage the lattice of the semiconductor material and this damage worsens device performance. The standard methods used to correct the lattice damage often reverse the deposition process itself by allowing the dopants to diffuse out of the film.
The deposition process is completed in two steps. First, a solid state diffusion source is deposited on the surface of the film in alternating layers of the dopant and an encapsulating semi conductor. Second, after removing the substrate from the reactor, an anneal is performed to drive in the dopants by diffusion from the source layer into and throughout the semiconductor film. A possible third step consists of removing the encapsulating material of the diffusion source. What results is a single highly doped semi conductor film, without any defects caused by introducing dopants beyond the In-Situ limit. the lattice damage which is standard to doping.
- In-situ doping minimizes damage from externally adding dopants to semiconductor and thus maintains lattice structure and a high fraction of activated dopants.