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Three-Dimensional Semiconductor Device Structures Using Channelled Ion Implantation and Annealing Techniques

IP.com Disclosure Number: IPCOM000036208D
Original Publication Date: 1989-Sep-01
Included in the Prior Art Database: 2005-Jan-28
Document File: 3 page(s) / 66K

Publishing Venue

IBM

Related People

Rutz, RF: AUTHOR [+2]

Abstract

A technique is described whereby three-dimensional semiconductor device structures are produced using channelled ion implantation and annealing methods. The concept concentrates on producing a very shallow conducting layer with an abrupt boundary, for improved MESFET and other semiconductor devices, and simultaneously buries conducting or insulating layers.

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Three-Dimensional Semiconductor Device Structures Using Channelled Ion Implantation and Annealing Techniques

A technique is described whereby three-dimensional semiconductor device structures are produced using channelled ion implantation and annealing methods. The concept concentrates on producing a very shallow conducting layer with an abrupt boundary, for improved MESFET and other semiconductor devices, and simultaneously buries conducting or insulating layers.

The concept applies to a variety of doped layer semiconductors, which use type III-V, IV, and II-VI crystals, and is particularly useful in producing devices such as light detectors with improved efficiencies, high frequency MESFETs, and enhanced design flexibility for use in complicated integrated circuits.

The process encompasses the depositing of dopant materials, such as Ge, Si, Sn, Mg, Be, Te and Se for III-V crystals, in thin films on semiconductor surfaces of crystals that have been carefully aligned. This enables at least one of the principal low-index planes to be perpendicular to the ion beam implant. Also, it involves implanting with a neutral ion, such as As+ or Ga+ in the case of GaAs, or another dopant ion of a type opposite to that deposited on the surface, subsequently removing the deposited dopant layer, and annealing at a high temperature.

The orientation is chosen to maximize channeling of the implant, a procedure which is novel in semiconductor device fabrication, since great efforts are normally employed to reduce channelling to a minimum. The channelling plays a critical role in that it promotes the concentration of recoil atoms from the deposited dopant layer in the crystal near the surface. At the same time, it greatly reduces the implant species concentration in that region, by concentrating it deep within the crystal. Therefore, two different doping layers can be formed within the crystal spatially separated by adjustments of the implant energies and doses.

The deposited dopant layer thickness should be kept thin, generally less than twenty angstroms, so as to not appreciably scatter the implanting beam. Deposition can be done by molecular beam evaporation, low pressure vapor depositio...