Reverse engineering outfit Chipworks has posted microscope cross-sections of parts of the 22-nm Ivy Bridge processor from Intel.
It shows that the much touted FinFETs, which Intel calls tri-gate transistors, are in fact trapezoidal. Chipworks broke up 64-bit, four-core Xeon E3-1230 CPUs intended for the server market, which Chipworks bought in Hong Kong.
What is odd is that Intel appears to have moved away from a rectangular section which it was showing in 2011.
In a statement Gold Standard Simulations has also waded into the debate. Its CEO Professor Ase Asenov said that there is speculation about the possible advantages and disadvantages of the trapezoidal, or almost triangular, shaped 'bulk' FinFET." GSS has performed a simulation analysis of the FinFET using its statistical 3-D TCAD simulator called Garand. Its simulation looked at the dependence of threshold voltage on gate length for the trapezoidal Intel transistor and an equivalent rectangular-fin transistor.
He said that the rectangular fin has better short channel effects. Still, the million-dollar question is if the almost-triangular shape is on-purpose design, or is this, what bulk FinFET technology can achieve in terms of the fin etching? We will only know when Intel lets people come up and see its etching.