Re: Easy TCAD question
First you should get the phosphorous into the silicon, probably by implantation.
So the statement would be something like
Implant phosphorus dose=1.0E16 energy=35 tilt=0
You will have to adjust the dose energy values to get to your final value but around 1.0E16 dose should result in 1E19. This will come before the diffuse statement.
The the thermal activation and diffusion of this implanted phosphorous is realised by the diffuse statement. The O2, N2,H2 etc is the ambient for the diffusion process and should not need to know about the phosphorous which is already in the silicon. For diffuse with N2, this means a non oxidising thermal anneal process which should be used.
So
diffuse temp=900 time=10
will default to a N2 ambient. This is all you need to thermally activate and redistribute the phosphorous as the TCAD program will do this for all impurities currently in the simulation (in the mesh). Note that the diffusion time is normally in minutes, so if you simulate a rapid thermal anneal, say 1080 deg C for 30 seconds, this will become
diffuse temp=1080 time=0.5
This would be the case for source drain implant and thermal activation. For earlier processes, for example the channel implants prior to gate oxidation, that will use the gate oxidation thermal cycle to activate and redistribute the impurities:
implant boron dose=3.5E12 energy=20 tilt=7 #implant low energy boron at 7 degrees
diffuse temp=850 time=45 H2O #Wet oxidation
The H2O tells the simulator that the oxidation is a wet ambient, therefore will oxidise faster and any exposed silicon will grow an oxide on its surface depending on the time, temperature and any existing oxide on the surface before this simulation step.
Hope this helps ...........