Low Power High-K/Metal Gate 28nm CMOS Solutions for High Performance Applications
GlobalFoundries Inc. is the world’s third largest independent semiconductor foundry, with its headquarters located in Milpitas, California. GlobalFoundries manufactures integrated circuits in high volume mostly for semiconductor companies such as AMD, Broadcom, Qualcomm, and STMicroelectronics.
High-K/Metal Gate (HKMG) is one of the most significant innovations in CMOS fabrication since the development of silicon VLSI. The 28nm technology is designed for the next generation of mobile smart devices demanding faster GHz processing speeds, lower standby power and longer battery life. To meet these demands, the 32/28nm HKMG solution is a “Gate-First” approach that shares the process flow, design flexibility, design elements and benefits of all previous nodes based upon poly SiON gates. This solution is far superior to present alternatives in scalability (performance, power, die size, design compatibility), cost (a typical foundry customer will save tens of millions of dollars over the course of a 28nm vs. 40nm product portfolio lifecycle) and manufacturability.
GLOBALFOUNDRIES’ 28nm-SLP technology is the low-power CMOS offering delivered on a bulk-silicon substrate for mobile applications. Relative to other 28nm technologies, it achieves its lower cost platform by substantially reducing process complexity and mask counts. It offers design flexibility with multi-channel length capability and the ultimate in small die size. Available options include multiple SRAM bit cells for high density and high performance.
Since this process downsizes the footprint and power utilization, it optimizes energy efficiency, which translates into significantly longer battery run times and fewer recharge cycles; the benchmark of wireless devices moving forward. The gate-first HKMG process utilizes a functional voltage below 0.8V, scaling 28nm performance and power proportionately against 40nm-LP poly SiON. Overall performance gains include a 49% higher frequency capability, a 44% reduction in energy utilization per switch and >25% reduction in leakage power per circuit . The 28nm- SLP, Gate-First process also supports standard overdrive practices providing additional performance and flexibility gains for a broader application base (wireless AND wired).
A significant benefit of 28nm-SLP technology is that it provides hefty analog “headroom” (Vcc-Vt) and low noise performance relative to the offerings of other foundries. Gate-First enables a reduction in design complexity by preserving design architecture and layout style, thereby leveraging design investments with IP reuse. This design compatibility helps reduce the overall risks of adopting 28nm.
The Super-Low Vt option provides a performance boost over traditional Vts at a given process node, opening the door for greater than 2GHz performance. The resulting performance boost with a minimal increase in power makes this option attractive to applications with specific thermal requirements that still require the largest performance envelope.
GLOBALFOUNDRIES’ industry-leading 28nm Systems-on-Chip (SoCs) design platform is based on high-k metal-gate (HKMG) technology. GLOBALFOUNDRIES is driving the global standard for new technologies such as High-k Metal Gate (HKMG) with several co-development partners including IBM, Renesas, STMicroelectronics, Samsung, and Toshiba. This 28nm HKMG solution is far superior to that currently pursued by the other leading pure-play foundries, in both scalability (die size, design compatibility, performance) and manufacturability. This 28nm solution is a “Gate-First” approach that shares the process flow, design flexibility, design elements and benefits of all previous nodes based upon poly SiON gate stacks.
The technology is available in super low-power (SLP), high performance-plus (HPP) and low power, high performance (LPH) technology offerings, to cater to the complex requirements of next-generation SoC’s.
The 28nm technologies are based on bulk silicon substrates, and are designed for a wide variety of applications from high performance such as graphics and wired networking to mobile computing and digital consumer to low power wireless mobile applications that require long battery lifetime.
All three SLP, HPP and LPH utilize high k metal gate (HKMG) technology for superior control of the channel with high on currents and low leakage current. Scheduled for risk production after the ramp of 32nm, 28nm is the second technology for high volume production at GLOBALFOUNDRIES that utilizes HKMG.
GLOBALFOUNDRIES’ HKMG enables full scaling from 40nm in area and performance; i.e., 28nm delivers twice the gate density of industry standard 40nm processes and an SRAM cell size shrink of more than 50 percent (cell size of 0.120 square micrometers for dense single port). 28nm transistors offer up to 60% higher performance than 40nm at comparable leakage with up to 50% lower energy per switch and 50% lower static power. As a leading manufacturer of x86 CPU’s, GLOBALFOUNDRIES well understands the constraints and trade-offs of performance, power and area.
28nm Super Low Power
28nm-SLP targets low-power applications including cellular base band, application processors, portable consumer and wireless connectivity devices. 28nm-SLP utilizes HKMG and presents a 2x gate density benefit, but is a lower cost technology in terms of the performance elements utilized to boost carrier mobilities.
28nm-SLP supports four Vt options – super low, low, standard, and high Vt with Vddnominal voltage of 1.0V. The I/O devices support 1.8V (with underdrive option to 1.5V) and , 2.5V (with underdrive 1.8V and 3.3V overdrive options) to meet different product specifications. 28nm-SLP also features a wide choice of metal stack options, optimized for density and power. Furthermore, a rich RF CMOS offering will be available in 2012, making it an ideal platform for the next generation of system-on-chip (SoC) wireless connectivity designs supporting multiple communication protocols.
28nm High Performance Plus (HPP)
28nm-HPP targets high performance networking and wired communication applications. The technology supports low, standard, and high Vt options with an operating voltage of 0.85V. The lower operating voltage is selected for the lowest possible active power , critical for networking and server products where carbon footprint is increasingly an important consideration. The I/O choices include 1.8V (with an underdrive option to 1.5V) to meet different product specifications. 28nm-HPP features a wide choice of metal options. 28nm-HPP technology provides a performance boost of as much as 10% over a competitive offering.
28nm Low Power, High Performance (LPH)
28nm-LPH technology complements the SLP technology, extending the frequency of operation for high-performance smartphones, high-end tablets, and notebook computers. The technology supports 4 Vts (low, standard, high and ultra-high) options with an operating voltage of 0.90V. Understanding the requirement for extended battery life needed for mobile environments, the technology comes with ultra-low leakage transistors as well as low leakage memories. When compared to 40nm, the technology can provide 50 percent active power reduction or 60 percent performance boost. The I/O devices support 1.8V (with underdrive option to 1.5V) and , 2.5V (with underdrive 1.8V and 3.3V overdrive options) to meet different product specifications. 28nm-LPH also features a wide choice of metal stack options, optimized for density and power.