Scott Hareland

High performance fully-depleted tri-gate CMOS transistors

Fully-depleted (FD) tri-gate CMOS transistors with 60 nm physical gate lengths on SOI substrates have been fabricated. These devices consist of a top and two side gates on an insulating layer. The transistors show near-ideal subthreshold gradient and excellent DIBL behavior, and have drive current characteristics greater than any non-planar devices reported so far, for correctly-targeted threshold voltages. The tri-gate devices also demonstrate full depletion at silicon body dimensions approximately 1.5 - 2 times greater than either single gate SOI or non-planar double-gate SOI for similar gate lengths, indicating that these devices are easier to fabricate using the conventional fabrication tools. Comparing tri-gate transistors to conventional bulk CMOS device at the same technology node, these non-planar devices are found to be competitive with similarly-sized bulk CMOS transistors. Furthermore, three-dimensional (3-D) simulations of tri-gate transistors with transistor gate lengths down to 30 nm show that the 30 nm tri-gate device remains fully depleted, with near-ideal subthreshold swing and excellent short channel characteristics, suggesting that the tri-gate transistor could pose a viable alternative to bulk transistors in the near future.

Tri-Gate fully-depleted CMOS transistors: fabrication, design and layout

Tri-Gate fully-depleted CMOS transistors have been fabricated with various body dimensions. These experimental results and 3-D simulations are used to explore the design space for full depletion, as well as layout issues for the Tri-Gate architecture, down to 30 nm gate lengths. It is found not only that the Tri-Gate body dimensions are flexible and relaxed compared to single-gate or double-gate devices, but that the corner plays a fundamental role in determining the device I-V characteristics. The corner device not only turns on at lower voltages due to the proximity of two adjacent gates, but the DIBL of this part of the device is much smaller than the rest of the transistor. The shape of the subthreshold I-V characteristics and the degree of DIBL control, as well as the early device turn-on are also greatly affected by the degree of body corner rounding. Examination of layout issues shows that the fin-doubling approach from using a spacer printing technique results in an increase in drive current of 1.2 times that of a planar device for a given width, though the shape of the allowed Tri-Gate fins has certain restrictions.

Impact of CMOS process scaling and SOI on the soft error rates of logic processes

Technology scaling, reduction in operating voltages, and the increase in cache size and circuit complexity have been key enablers to achieving the performance improvement expectation dictated by Moores Law. The resulting reduction in the node charge of circuit latches and cache cells has resulted in an ever increasing soft error rate (SER) estimation for logic components. This paper reports the SER impact of process scaling over four technology generations (0.35, 0.25, 0.18, 0.13 /spl mu/m) and provides an experimental assessment of alpha and, for the first time, neutron SER on advanced SOI processes, which have been considered as a possible method to reduce the SER of advanced technologies.

Silicon nano-transistors and breaking the 10 nm physical gate length barrier

In this paper, the performance and energy delay trends for research devices down to 10 nm and also discusses the 10 nm barrier and potential ways to break it were explored.

Silicon nano-transistors for logic applications

Abstract Silicon transistors have undergone rapid miniaturization in the past several decades. Recently reported CMOS devices have dimensional scales approaching the “nano-transistor” regime. This paper discusses performance characteristics of a MOSFET device with 15 nm physical gate length. In addition, aspects of a non-planar CMOS technology that bridges the gap between traditional CMOS and the nano-technology era will be presented. It is likely that this non-planar device will form the basic device architecture for future generations of nano-technology.