High Concentration Doping of Semiconductors through In-Situ Deposition

Technology #14916

Questions about this technology? Ask a Technology Manager

Download Printable PDF

Image Gallery
FIG. 1 is a schematic depiction of the processing conducted in a two-step in situ-ex situ process for high-concentration activated doping of a semiconducting materialFIGS. 2A, 2B, and 2C are plots of the conduction and valence bands at the band gap of bulk intrinsic Ge, tensile-strained intrinsic Ge, and tensile strained n+ doped Ge, respectively
Categories
Inventors
Professor Lionel Kimerling
Department of Material Science and Engineering, MIT
External Link (dmse.mit.edu)
Jurgen Michel
Electronic Materials Research Group, MIT
External Link (photonics.mit.edu)
Jonathan Bessete
Materials Processing Center, MIT
Rodolfo Camacho-Aguilera
Materials Processing Center, MIT
Yan Cai
Department of Materials Science & Engineering, MIT
Jifeng Liu
Materials Processing Center, MIT
Managed By
Jim Freedman
MIT Technology Licensing Officer - Chemicals, Instruments, Consumer Products
Patent Protection

High-Concentration Active Doping in Semiconductors and Semiconductor Devices Produced by Such Doping

US Patent Pending US 2014-0254620
Publications
Toward a Germanium Laser for Integrated Silicon Photonics
IEEE, October 13 2009, 124-131
High n++ doped germanium: Dopant in-diffusion and modeling
Group IV Photonics (GFP), 2011 8th IEEE International Conference, vol., no., pp.228,230, 14-16 Sept. 2011

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.

Applications

  • Optical, electrical, or electro-optical devices (HFETs, LD, and LEDs)
  • Germanium light emitters

Problem Addressed

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.

Technology

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.

Advantages

  • In-situ doping minimizes damage from externally adding dopants to semiconductor and thus maintains lattice structure and a high fraction of activated dopants.