Semiconductors GaN, AlGaN -- Questions about abbreviations

[Deleted member 655103]

Hi, I have some chemical abbreviation which I do not understand. Please can you tell me what those abbreviations mean?

1. u-GaN 800nm (C:2E16 at/cm³) (I do not understand what "u" stands for; GaN is Gallium Nitride, 800 nm is thickness of layer, C is concentration of atoms per cm³ but I am not sure concentration of what?)

2. C:GaN 700nm (C:2E19 at/cm³) (what is C before GaN and again concentration 2E19 at/cm³ of what?)

3. AlN/Al0.1GaN 5/25 nm (I do not know what 0.1 in Al0.1GaN means; I know that 5nm is Alluminiu Nitride, 25nm Alluminium Gallium Nitride)

4. Al_0.3Ga_0.7N (what means 0.3 and 0.7? I think it means that 30% of Al and 70% of Ga, but what about N (nitrogen)? is it 50% of Nitrogen and from remaining 50% is 30%Al and 70% of Ga so over all 50%N, 15%Al, 35%Ga? Am I wrong?

Thanks for answers!

 

[TeethWhitener]

u-GaN 800nm (C:2E16 at/cm3) (I do not understand what "u" stands for; GaN is Gallium Nitride, 800 nm is thickness of layer, C is concentration of atoms per cm3 but I am not sure concentration of what?)

"u" means undoped. The C:2E16 is the concentration of carbon atoms in the gallium nitride.

2. C:GaN 700nm (C:2E19 at/cm3) (what is C before GaN and again concentration 2E19 at/cm3 of what?)

Again, C is carbon here.

AlN/Al0.1GaN 5/25 nm (I do not know what 0.1 in Al0.1GaN means; I know that 5nm is Alluminiu Nitride, 25nm Alluminium Gallium Nitride)

This means that aluminum is a dopant in GaN at up to 10 at%.

Al0.3Ga0.7N (what means 0.3 and 0.7? I think it means that 30% of Al and 70% of Ga, but what about N (nitrogen)? is it 50% of Nitrogen and from remaining 50% is 30%Al and 70% of Ga so over all 50%N, 15%Al, 35%Ga? Am I wrong?
Thanks for answers!

This is just basic stoichiometry, but presented in a way that may not be familiar from intro chemistry classes (the convention is, however, standard in solid state chemistry and physics). Pure GaN has one gallium atom for every nitrogen atom. Al_0.3Ga_0.7N has 0.3 aluminum atoms and 0.7 gallium atoms for every nitrogen, so in terms of atom percent, it's 50% N,15% Al, 35% Ga.

 

[Deleted member 655103]

Thank you for your answer.
I am little bit confused why do we have concentration of Carbon in undoped u-GaN? There should be no Carbon or does it mean that even if it is clean GaN there is still some carbon present but we did not add it into GaN by purpose?

 

[TeethWhitener]

Actually, I think I was wrong. I assume that the C:2E16 at/cm³ refers to the carrier concentration: so undoped GaN has no carbon in it, but the carrier concentration in this case would be 2E16 cm^-3. What's throwing me off is the units of at/cm³, which implies an atomic dopant concentration, instead of a carrier concentration. Where are these numbers coming from?

 

[Deleted member 655103]

Those numbers are parameters of layers in semiconductor parts. This is how they were fabricated. Thanks for your help.

 

[TeethWhitener]

Those numbers are parameters of layers in semiconductor parts. This is how they were fabricated. Thanks for your help.

NB--The range of numbers (10¹⁶-10¹⁹) suggests an atomic dopant as well. Carrier concentrations tend to be 10¹²-10¹⁵ cm^-3. You might check the supplier's data sheet on the semiconductor if you have it.