Compound semis to play key role at IEDM 2015
III-V nanowires, IGZO transistors and GeSn lasers featured in US conference
At the IEEE International Electron Devices Meeting in Washington DC later this week, compound semiconductors will feature in a number of key papers. As a pre-eminent forum for reporting technological breakthroughs in semiconductor and electronic device technology, the conference is regarded as a guide to what the industry might expect in future devices and emerging materials.
A research team at the National University of Singapore, for example, will be describing the first use of vertically stacked III-V nanowires to integrate high electron-mobility III-V semiconductors monolithically and cost-effectively with traditional CMOS silicon technology at sub-7 nm technology nodes. The researchers built a sub-150nm high-quality GaSb buffer layer on silicon and multi-gate InAs nFETs and GaSb pFETs from stacked InAs or GaSb nanowires, respectively. The fabrication technology is suitable for both high-performance and low-power logic applications, according to the researchers.
National Nano Device Laboratories in Taiwan will discuss gate-all-around nanowire MOSFETs with diamond-shaped germanium and GeSi nanowire channels. The researchers are seeking to find a way to more effectively use germanium as the channel material in multi-gate device configurations for scaling beyond the 10-nm technology node. The researchers made germanium and GeSi nanowires into diamond cross-sectional shapes and used the nanowires as suspended channels ina gate-all-around MOSFET configuration.
A team from Japan's Semiconductor Energy Laboratory will explain how it made 20nm gate-all-around MOSFETs with low off-state currents of <0.1pA and cutoff frequencies exceeding 10GHz. The transistors were made from thin films of indium-gallium-zinc-oxide (IGZO) and built using a self-aligned process that eliminated overlaps from the gate to the source and drain. The low off-current allowed for data retention of >10 days at 125degC, when integrated in a DRAM memory cell.
Fujitsu researchers will report using InAlGaN and a novel double-layer SiN passivation technique to build 80nm-channel-length InAlGaN/GaN power HEMTs with a record 3W/mm output power density at 96GHz, which is 60 percent improvement over the best results reported to date. The HEMTs' power and reliability performance is suitable for use in amplifiers from 75 to 110GHz.
A European research collaboration led by Germany's Forschungszentrum Juelich institute, will report on a silicon-based direct-bandgap GeSn micro-disk laser that emits at a lasing wavelength of 2.5Âµm at a power output of 221 kW/cm2. The device was built using standard CMOS-compatible processing and was monolithically integrated on a silicon platform.