Morphology with and without susceptor
A simple experiment that has never been done is to make a direct comparison between annealing inside and outside the susceptor. Intuitively, we would expect the morphologies to be quite different since the heating mechanism is different for both cases. Inside the susceptor, the film is heated through blackbody radiation from the susceptor. Without the susceptor, the films are heated “directy” by the lamp radiation.
Both these 15 nm films were annealed at 1000 C with a ramp rate of 50 C/s.
We find that the porosity increases dramatically when a film is annealed without the susceptor. This could mean the film is getting hotter by direct heating from the lamps.
For now, I see no advantage in using the susceptor for annealing full wafers since the uniformity has been quite good recently across a 4-inch substrate.
It seems that denser pores will be formed as a result of faster heating rate. I think the difference between with and without the susceptor is that the film could get higher heating rate compared with susceptor. Do you think it’s same like the affect of ramp rate of RTP?