Doping Level of Substrates

university wafer substrates

Moderate Doping Level for Good PL Intensity

A PhD candidate requested the following quote:

I need as photoluminescence (PL) test sample. Can be a partial wafer (like item #9412 below). Should have moderate doping level for good PL intensity. ~1e18 cm^-3. Looking for lowest cost.

Reference #92247 for specs and pricing.

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Doping Level of Ph Doped Silicon Wafers

A director of research and development requested help with the following doping level question:

I'd like to have 8-in n-type Si wafers with very small resistivity. How low can you get for me with qty 10 ~ 20? It's an urgent need.

  1. For their surface grade, does EPI mean the wafers are epitaxially grown on top of Si substrates? If that's case, what is the resistivity for their substrate? Since I'd like to have low resistivity all the way through the wafers, this is very important to me.
  2. For "PH Red" wafer, can you tell me what the difference between normal Ph-doped Si wafers? Unstable because of high doping level? Exceeding PH solid solubility?
  3. Does the sale price refer to each Si wafer? Is there any minimum quantity?

Reference #92394 for specs and pricing.

Doping Levelof Intrinsic Silicon Wafers

A physics professor requested a quote for the following:

I would like to know the doping concentration in "carriers/cm3" of the following spec:

2" Intrinsic (100) 50 microns DSP

Reference #91641 for specs and pricing.

Magnesium (Mg) Gallium NItride Doping Level

A Nanostructure researcher requested help with the following:

Mg doped GaN on sapphire would work well. For this order, I will have use purchase order instead of credit card. Could you please send me a formal quotation (with the specifications, such as layer thickness, dislocation densities, doping level etc.)?

Reference #93834 for specs and pricing.

Doping Level of (110) P-Type Silicon Wafers

An engineering student requested a quote for the following:

I would like to order Si(111) samples, 525 micrometre thick, P- doped , n- type 1-10 ohmxcm resistivity oriented to within 0.5 degree of (111) plane. 

I dont use P(111). please see the attached excel file for some of the Silicon wafers that I need.
I want you to sent me a quatation for the Silicon wafers at the attached exel file.

do you have the silicon wafers having the following properties:
[100] and [110] p-doped (doping level of the order of 10^16-10^18 cm-3) n-type with resistivity 1-10 ohm-cm (but 0.01-0.03 ohm-cm is better if it is available) crystal orientation 0.5 degree thickness 0.3 mm (or 300 um-524 um).

Reference #94673 for specs and pricing.

What is the Doping Level of N++ Doped Silicon Wafers?

A postdoctoral student requested a quote for the following:

Can we get say 30 wafers of 300nm thermox (single side polished),
10 300nm thermox (one side polished, other side Si exposed) and 10
500nm thermox (single side polished)? If yes what are the prices?

Do you have n++ doped wafers with As or P dopants, resistivity
<0.006 ohm -cm. We just need a highly conducting silicon base, if
you've resistivity close to it and cheaper option, please let me know.

Are there any other options for dopants, doping level (n++) and thickness (300nm, 600nm)?

Reference #96055 for specs and pricing.

 

What is Doping Level?

"Doping level" is a term often used in the context of semiconductor physics and materials science. It refers to the process of intentionally introducing impurities into an intrinsic (pure) semiconductor to change its electrical properties. The purpose of doping is to increase the number of free charge carriers (electrons or holes) in the semiconductor material, which enhances its conductivity.

There are two main types of doping:

  1. N-type Doping: This involves adding impurities that have more valence electrons than the semiconductor. For example, adding phosphorus (which has five valence electrons) to silicon (which has four valence electrons) creates an N-type semiconductor. The extra electron from the phosphorus atom becomes a free electron, increasing the semiconductor's conductivity.

  2. P-type Doping: This involves introducing impurities with fewer valence electrons than the semiconductor. For example, adding boron (which has three valence electrons) to silicon creates a P-type semiconductor. The absence of an electron, known as a "hole," can move around and acts as a positive charge carrier.

The "doping level" specifically refers to the concentration of these impurities in the semiconductor material. The level of doping directly influences the electrical properties of the semiconductor, such as its conductivity and the behavior of p-n junctions (junctions between P-type and N-type semiconductors), which are critical in electronic devices like diodes and transistors.

In a broader sense, "doping" is also a term used in sports to refer to the use of prohibited performance-enhancing drugs by athletes. However, in the context of your question, it seems more related to the scientific and engineering domain.

Gallium Phosphide Doping Level

An engineering fellow requested the follwoing quote for GaP substrates.

Question:

Is the doping level on this wafer accurate (i.e. 10^14)?  I assume many of the others on your list are typos (i.e.  the item just above this one listed with a doping concentrations of 1.4E+06 is supposed to read 1.4E+16).  Is that right?  Please it's above as 10^14 level concentration and get back to me.  I think I would buy it and test it.  If I like it, could I get this made for me in a 1,000um thick wafer (i.e. does the maker have more of material they can process?)

GaP Item #186B - 2" Undoped Si (111) 450um SSP
Res n-type 3.5E10
Nca/cm3 1.4E6
Mobile cm2/Vs
EPD/Cm2
Epi Ready PF@(110) SF@(112)

Answer:

Above parameters are correct, or at least this is what was measured {4 point Resistivity and Hall effect measurement through diffused gold electrodes} on the section of the ingot from which the wafers were sliced.
Item #186A has Nc=6×10^14/cc. This is consistant with its high Resistivity.
Item #186B has Nc=1.4×10^6/cc {that is 10 to the sixth power, not 10 to the 16th power}. Again, this is consistant with its very high resistivity 3.5×10^10 Ohmcm. This is a Semi Insulating GaP, and extremely high resistivity at that. YES, please do test this material.

As far as I can see we do not have on hand a GaP:-[111] ingot from which to make 1mm thick wafers. However, I think that we do have a 2" Semi Insulating GaP:-[100] ingot at Nc levels about as low as #186B above.

Reference #95041 for specs and pricing.

How do you determine the doping level of a silicon substrate?

Figuring out how much doping is in a silicon base isn't straightforward; it needs several methods, each giving us a unique look into the amount and kind of dopants hanging out inside the silicon. Here are some common methods:

  1. Four-Point Probe Method: This technique measures the resistivity of the silicon substrate. By applying a known current through the outer probes and measuring the voltage between the inner probes, the resistivity can be calculated. Since the doping level is inversely related to resistivity, this method gives an indirect measure of the doping concentration.

  2. Hall Effect Measurement: This method involves placing the silicon substrate in a magnetic field. When a current is passed through the substrate, the Hall voltage (perpendicular to both current and magnetic field) is measured. This voltage is related to the number and type (positive or negative) of charge carriers, which in turn gives information about the doping level.

  3. Secondary Ion Mass Spectrometry (SIMS): SIMS is a more direct method where a focused ion beam is used to sputter the surface of the substrate. The ejected particles (secondary ions) are then analyzed to determine the composition and concentration of dopants.

  4. Capacitance-Voltage (C-V) Profiling: This technique is used to determine the doping profile across the depth of a semiconductor. It involves measuring the capacitance of a metal-oxide-semiconductor (MOS) capacitor made on the silicon substrate as a function of the applied voltage. This allows you to clearly see the depth-dependent variations in doping concentration.

  5. Electron Microscopy: Techniques like Transmission Electron Microscopy (TEM) combined with Energy Dispersive X-ray Spectroscopy (EDX) can be used to visually inspect the substrate and determine the elemental composition, including dopants.

  6. Spreading Resistance Profiling (SRP): SRP is another method to determine the doping profile of a substrate. So, what this process really does is, it uses a pair of probes that are super close together to touch the surface of our substrate. Then, by measuring how much resistance there is while we dig deeper into it - that's how we figure out everything about its profile!

Every method brings its own perks and pitfalls to the table, with your pick hinging on what level of precision you're chasing, the specific traits of the silicon substrate under scrutiny, and how much detail you need.