What are Doped Semiconductors?

university wafer substrates

Heavily Doped Semiconductors

A PhD candidate requested a quote for the following.

Need an epitaxial insulating crystal on a heavily doped semiconductor (preferably Si). GaN on Si could work for this, but cost other cost effective options are desired.

Reference #99738 for specs and pricing.

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Degenerately Doped Semiconductor

An electrical engineering student requested a quote for the following.

Can you please send me the price quotation including shipping cost for following chemicals:

I need degenerately doped n++ Si substrate with thermally grown SiO2 (300 nm), that is I need n++ Si which is different from n-type Si in terms of doping level.

UniversityWafer, Inc. Responded:

Degenertively doped semiconductor material is one that behaves more like a metal than a semiconductor, with respect to temperature.
This normally means Ro<0.020 Ohmcm.

Such p-type wafers are normally doped with Boron.
Such n-type wafers are normally doped with Antimony (0.01-0.02)Ohmcm or with Arsenic (0.001-0.005)Ohmcm. It is seldom that one can find n-type wafer degeneratively doped with Phosphorus.

Reference #221401 for specs and pricing.

 

 

Doped Semiconductor Measured Numerical Carrier Concentration

An assistant professor requested the following quote.

I am looking to buy a piece of doped semiconductor material with the measured numerical carrier concentration provided. It doesn't matter what semiconductor material it is.

Does university wafer sell any semiconductors that you know the numerical value of the carrier concentration? 

Reference #105780 for specs and pricing.

What are Doped Semiconductors?

Doped semiconductors are semiconductors whose electrical properties have been intentionally altered by adding small amounts of impurities, known as dopants, to enhance conductivity and control specific electronic characteristics.

Types of Doped Semiconductors:

1. N-type Semiconductor (Negative-type)

  • Dopant: Elements from Group V (e.g., phosphorus, arsenic, antimony).
  • Mechanism: Dopants provide extra electrons (negative charge carriers).
  • Majority carriers: Electrons.
  • Conductivity: Increased due to excess electrons.
  • Example: Silicon doped with phosphorus (Si:P).

2. P-type Semiconductor (Positive-type)

  • Dopant: Elements from Group III (e.g., boron, gallium, aluminum).
  • Mechanism: Dopants create "holes" (positive charge carriers) due to missing electrons.
  • Majority carriers: Holes.
  • Conductivity: Increased due to extra holes.
  • Example: Silicon doped with boron (Si:B).

Why Doping Matters:

Pure silicon (intrinsic semiconductor) has limited electrical conductivity. By introducing dopants, its conductivity can be precisely controlled to create:

Typical Dopant Concentrations:

  • Lightly-doped: 1013−101610^{13} - 10^{16} atoms/cm³
    (Used for intrinsic devices, sensors, or optical applications.)

  • Moderately-doped: 1016−101810^{16} - 10^{18} atoms/cm³
    (Used in standard transistors and IC fabrication.)

  • Heavily-doped: >1018>10^{18} atoms/cm³
    (Used for contact layers, highly conductive regions.)

Applications of Doped Semiconductors:

Doping allows engineers to tailor semiconductor properties precisely for various technological applications, making it fundamental to modern electronics.