News Article
Highest performing III-V metal-oxide FETs
III-V MOSFETs could lower power consumption for the next generation of servers
UCSB researchers say they have introduced the highest performing III-V metal-oxide semiconductor (MOS) field-effect transistors (FETs) at the 2014 Symposium on VLSI Technology.
The University of California, Santa Barbara (UCSB) research promises to help deliver higher semiconductor performance at lower power consumption levels for next-generation, high-performance servers.
The research is supported by the Semiconductor Research Corporation (SRC), a university-research consortium for semiconductors and related technologies.
UCSB says its III-V MOSFETs, for the first time in the industry, exhibit on-current, off-current and operating voltage comparable to or exceeding production silicon devices - while being constructed at small dimensions relevant to the VLSI (very-large-scale integration) industry.
For the past decade, III-V MOSFETs have been widely studied by a large number of research groups, but no research group had reported a III-V MOSFET with a performance equal to, let alone surpassing, that of a silicon MOSFET of similar size.
In particular, UCSB’s transistors possess 25nm gate lengths, an on-current of 0.5mA and off-current of 100nA per micron of transistor width and require only 0.5 volt to operate.
“The goal in developing new transistors is to reach or beat performance goals while making the transistor smaller - it is no good getting high performance in a big transistor,” says Mark Rodwell, professor of Electrical and Computer Engineering at UCSB. “In time, the UCSB III-V MOSFET should perform significantly better than silicon FinFETs of equal size.”
To reach this breakthrough in performance, the UCSB team made three key improvements to the III-V MOSFET structure. First, the transistors use extremely thin semiconductor channels, some 2.5nm (17 atoms) thick, with the semiconductor being InAs. Making such thin layer improves the on-current and reduces the off-current. These ultra-thin layers were developed by UCSB Ph.D student Cheng-Ying Huang under the guidance of Arthur Gossard.
Next, the UCSB transistors use very-high-quality gate insulators, dielectrics between the gate electrode and the semiconductor. These layers are a stack of alumina (Al2O3, on InAs) and zirconia (ZrO2), and have a very high capacitance density. This means that when the transistor is turned on, a large density of electrons can be induced into the semiconductor channel.
Third, the UCSB transistors use a vertical spacer layer design. This vertical spacer more smoothly distributes the field within the transistor, avoiding band-to-band tunnelling. As with the very thin InAs channel design, the vertical spacer makes the leakage currents smaller, allowing the transistor's off-current to rival that of silicon MOSFETs. The overall design, construction and testing of the transistor was led by UCSB Ph.D student Sanghoon Lee under Rodwell’s guidance.
“The UCSB team’s result goes a long way toward helping the industry address more efficient computing capabilities, with higher performance but lower voltage and energy consumption,” says Kwok Ng, Senior Director of Device Sciences at SRC. “This research is another critical step in helping ensure the continuation of Moore’s Law - the scaling of electronic components.”
This article was adapted from an article by Semiconductor Research Corporation.
The University of California, Santa Barbara (UCSB) research promises to help deliver higher semiconductor performance at lower power consumption levels for next-generation, high-performance servers.
The research is supported by the Semiconductor Research Corporation (SRC), a university-research consortium for semiconductors and related technologies.
UCSB says its III-V MOSFETs, for the first time in the industry, exhibit on-current, off-current and operating voltage comparable to or exceeding production silicon devices - while being constructed at small dimensions relevant to the VLSI (very-large-scale integration) industry.
For the past decade, III-V MOSFETs have been widely studied by a large number of research groups, but no research group had reported a III-V MOSFET with a performance equal to, let alone surpassing, that of a silicon MOSFET of similar size.
In particular, UCSB’s transistors possess 25nm gate lengths, an on-current of 0.5mA and off-current of 100nA per micron of transistor width and require only 0.5 volt to operate.
“The goal in developing new transistors is to reach or beat performance goals while making the transistor smaller - it is no good getting high performance in a big transistor,” says Mark Rodwell, professor of Electrical and Computer Engineering at UCSB. “In time, the UCSB III-V MOSFET should perform significantly better than silicon FinFETs of equal size.”
To reach this breakthrough in performance, the UCSB team made three key improvements to the III-V MOSFET structure. First, the transistors use extremely thin semiconductor channels, some 2.5nm (17 atoms) thick, with the semiconductor being InAs. Making such thin layer improves the on-current and reduces the off-current. These ultra-thin layers were developed by UCSB Ph.D student Cheng-Ying Huang under the guidance of Arthur Gossard.
Next, the UCSB transistors use very-high-quality gate insulators, dielectrics between the gate electrode and the semiconductor. These layers are a stack of alumina (Al2O3, on InAs) and zirconia (ZrO2), and have a very high capacitance density. This means that when the transistor is turned on, a large density of electrons can be induced into the semiconductor channel.
Third, the UCSB transistors use a vertical spacer layer design. This vertical spacer more smoothly distributes the field within the transistor, avoiding band-to-band tunnelling. As with the very thin InAs channel design, the vertical spacer makes the leakage currents smaller, allowing the transistor's off-current to rival that of silicon MOSFETs. The overall design, construction and testing of the transistor was led by UCSB Ph.D student Sanghoon Lee under Rodwell’s guidance.
“The UCSB team’s result goes a long way toward helping the industry address more efficient computing capabilities, with higher performance but lower voltage and energy consumption,” says Kwok Ng, Senior Director of Device Sciences at SRC. “This research is another critical step in helping ensure the continuation of Moore’s Law - the scaling of electronic components.”
This article was adapted from an article by Semiconductor Research Corporation.
