Is it needed to stress the layers to have lower contact resistance?
Is this stress useful or disrupt the layers in a bad way?
A slower, multi-step anneal might prove more useful for you. Rapid and slow annealing work in the same way effectively, causing the diffusion of your contacts or the shifting of their fermi level towards the conduction band depending on what you're doing. The problem with a rapid shift in temperature is it can potentially detriment the morphology of your contacts/material, causing the resistance to increase again.
Normally, in semiconductor technology, metals are used as low resistance contact. Metals readily diffuse into semiconductor material doping it, often in a degenerate way, helping to form an ohmic contact. To optimally control the diffusion is common use a slow annealing. Sometimes it is preferred to use a rapid anneling and a rapid cooling to induce defects at the interface between the two materials. These defects can channel the electrical current facilitating the formation of a low resistance contact.
Dear Khalim,
in some cases RTA may be the better method:
https://www.researchgate.net/publication/264049137_Robust_recipe_for_low-resistance_ohmic_contacts_to_a_two-dimensional_electron_gas_in_a_GaAsAlGaAs_heterostructure
Kind regards,
Arne
Article Robust recipe for low-resistance ohmic contacts to a two-dim...
Depending on your substrate and the nature of the deposited metallic material and also the technique deposition: There are many technological parameters to take into account. Your question is so general and we can’t give a concise response.
Example: when we use metallic pastes for silicon solar cell, the RTA annealing with an optimized temperature profile vive the best results with a metallic contact characterized with a very lox series resistance. If we use a metallic powder (Electronic-Grade) with a physical deposition technique like Sputtering or Gun evaporation at a heated substrate (200-400) or in some cases at ambient temperature flowed with a forming gas anneal to ameliorate the metal/semiconductor at interface an ohmic contact annealing.
So you must precise your use file and the device, semiconductor to type and the used metal; Ti, Ni, Ag, Ta, ...etc.
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