There are a number of pros and cons when FDSOI is discussed partly because the core issues associated with FDSOI are not properly addressed. One of the critical issues with FDSOI is its scalerbility. According to device theory the SOI thickness or transistor channel thickness required to suppress transistor leakage current or short channel effect is 7nm for 28nm node, 3.5nm for 14nm node and 2.5nm for 10nm node. Soitec, the largest SOI wafer manufacturer, announced at 2011 SOI conference that what it can deliver in volume manufacturing are minimum 12nm SOI and 25nm UTBB(ultrathin buried oxide), meaning that ST has to thin down 12nm SOI to obtain the final 7nm SOI uniformly and reliably across 350mm wafers. If ST' FDSOI is superior to planer bulk 28nm and is available today as ST claims, why ARMH and Qulcomm's Snapdragon chips are manufactured for over two years by TSMC, but not by ST? 14nm and 10nm FDSOI require the SOI thickness of 3.5nm and 2.5nm, respectively. Such thin FDSOI not only physically can't be manufactured but also subject to so called quantum confinement or device physics limit. Therefore, ST's 14nm node will be the end of FDSOI scaling. On the other hand, FinFET will be extended to 4nm node because the fin width that is equivalent to SOI thickness requires 4nm in order to suppress the transistor leakage current. 4nm is equal to the gate length in this case. Furthermore, Intel's FinFET doesn't rely on Soitec wafers. Therefore, FDSOI can't be a viable alternative to FinFET. SKim
Can somebody explain why FDSOI 20nm can be in the same cost range as bulk CMOS? where did $400-500 wafer cost delta go? Is there fundamental processes,design assumption initiated doing this comparison? Performance is one thing, cost is a different issue. this can always be used for extreme low power application, which can tolerate higher pricing.
Unless the yield can reach 80% robustly, even such cost analysis doesn't mean much for die cost if it targetted for general mobile phone applications.
The industry in Japan actually has very deep FDSOI roots. Nobuyuki SUGII's (then) Hitachi team had a break-through paper at IEDM in 2008 “Comprehensive Study on Vth Variability in Silicon on Thin BOX (SOTB) CMOS with Small Random-Dopant Fluctuation: Finding a Way to Further Reduce Variation,” -- but they called it SOTB, so people might not realize it is indeed planar FD-SOI. Dr. Sugii first wrote about it for ASN in 2009 (http://www.advancedsubstratenews.com/2009/05/less-than-ever/), and in 2010 argued that the benefits would even be there for nodes as far back as 40/65nm (where there's still plenty of business see http://eda360insider.wordpress.com/2011/09/07/where-is-the-mainstream-ic-process-technology-today-28nm-40nm-65nm/). See Dr. Sugii's piece making the argument for the older nodes at http://www.advancedsubstratenews.com/2010/07/the-moment-is-now/. So in short, they might not need much convincing!
For those looking for more FDSOI info, the Consortium's got a huge amount -- see www.soiconsortium.org.
this article reminded me of grade-school social blather: X saw Y kissing Z at the party... couldn't we have a genuinely informative article on what properties fdsoi brings, how much trouble it'll cause, etc.
Blog Doing Math in FPGAs Tom Burke 2 comments For a recent project, I explored doing "real" (that is, non-integer) math on a Spartan 3 FPGA. FPGAs, by their nature, do integer math. That is, there's no floating-point ...