Source: Samsung explores gate-last high-k

Samsung vs. TSMC
In any case, Samsung will likely become one of the first foundries to roll out a high-k/metal-gate solution for customers. ''We think that gate-first is best suited for today's needs,'' Samsung's Hunter said.

At the recent Semico Outlook conference, Hunter also provided six basic reasons why Samsung believes it will succeed in the foundry business.

It's unclear if Samsung will implement gate-last at 22-nm. It has quietly assembled an R&D group that is exploring the technology. It's also unclear if IBM's fab club will make the switch or not.

Rival Taiwan Semiconductor Manufacturing Co. Ltd. (TSMC) has already switched camps. Originally, TSMC was planning to go with a gate-first technology. Now, it will go with gate-last.

''The first high-k metal gate we call 28 HP for the high performance application will be introduce the end of September this year. This is the first high-k metal gate introduction for low power applications,'' said Shang-Yi Chiang, senior vice president of R&D at TSMC, in a recent presentation.

''At this moment the only way we know how to do that is the gate last approach,'' he said. ''This is a controversial issue in the industry. The industry (has) diverged to two approaches. One is what we call gate-first. Another is gate-last.''

Gate-last, according to TSMC, has some advantages. ''The gate-last process is a little more complicated and a lot more difficult to do. But after you learn that (process), the challenge is very much the same, and the cost is pretty much the same,'' he said.

''The real key difference in the gate-last approach (is that) we use two different gate metals, one metal for the P channel and one metal for N channel. For the gate-first approach, we use the same metal for N and P channel. In gate-last, we can freely adjust voltage for both N channel and P channel. Gate-first has difficulty doing that. So that's a major difference,'' he added.