The results of the most recent SOI Consortium benchmarking study detail the interest of planar FD-SOI as early as the 28nm and 20nm technology nodes, in terms of performance, power and manufacturability. This 3-part blog series looks further at some of the implications.
The SOI Industry Consortium announcement at the end of the year provided silicon proof that FD-SOI handily beats traditional planar CMOS devices built on bulk-silicon substrates even at 28nm.
Armed with the information from the 28nm bulk vs. FD-SOI benchmarking study, the SOI Consortium members then did new benchmark simulations at the 20nm node. This confirmed the trends they saw in silicon at 28nm. When comparing FD-SOI technology to bulk technology specifically intended for System-on-Chip (SOC):
Here’s the graphic that says it all. Follow the suggestions in the annotations to see how the power vs. performance trade-off works.
To use this graph: pick any point on the lower, bulk line, then move horizontally to the left to see how much less power it will take to hit the same frequency with FD-SOI.
(a) Reverse back-bias allows you to cut leakage, here by a factor of 10
(b) This line is 20 nm FD-SOI with back biasing
(c) Or with back-biasing FD-SOI, you can hit over 269 MHZ using 120 mW at 1 V power supply
(1) This line is 20 nm Bulk
(2) This line is 20 nm FD-SOI
(3) Bulk takes over 130 mW to hit frequency of about 223 MHz with supply voltage of 1 V
(4) To hit the same with FD-SOI takes just over 100 mW and a supply voltage of just 0.9 V
(Courtesy: SOI Consortium)
STMicroelectronics, IBM, ARM, GLOBALFOUNDRIES and other leading semiconductor companies participated, each tackling different aspects of the study. The joint research was performed by using an FD-SOI process to fabricate 28nm chips. Test results on these chips were in line with predictions from computer-based models previously developed to benchmark FD-SOI device performance, confirming the models’ reliability – key for both designers and foundries.
Editor’s note: Special thanks to the SOI design experts who helped with the explanations in this blog.