> HZO is a ferroelectric. That is, it has a crystal structure that allows it to maintain an internal electrical field even when no external voltage is applied. (Conventional dielectrics don’t have this inherent electrical field.) When a voltage is applied to the transistor, HZO’s inherent electric field opposes it. In a transistor, this leads to a counterintuitive effect: A decrease in voltage causes an increase in the charge stored in HZO. This negative capacitance response effectively amplifies the gate control, helping the transistor’s 2D electron cloud accumulate charge and boosting the on-state current.
> Leakage current is a well-known problem in these kinds of transistors, “so integrating an innovative ferroelectric layer into the gate stack to address this has clear promise,” says Aaron Franklin, an electrical engineer at Duke University, in Durham, N.C. “It certainly is an exciting and creative advancement.”
I'm wondering if this will eventually transition out of power electronics into other sorts of electronics. Sounds like they've got their next five years planned just looking at power electronics though.
Negative capacitance in a field effect transistor is not new. In fact this has been shown mire than a decade ago. The reason it won't make its way into modern chips is because the materials used to make the ferroelectrics aren't CMOS foundry compatible.
Hafnium and zirconium dioxide are CMOS foundry compatible.
Hafnium dioxide has been the gate dielectric for MOS transistors in all dense CMOS processes for a couple of decades. It is certainly used in whatever smartphone or computer you have.
With the former gate dielectric, silicon dioxide, it was impossible to make MOS transistors as small as in modern processes, because it has a too low dielectric constant, which would have required impossibly thin gate layers (for high enough gate capacitances).
Hafnium dioxide has a much higher dielectric constant, allowing to achieve the same gate capacitance at a manageable gate thickness.
The chemical behaviors of hafnium and zirconium are almost identical, their similarity being as great as between rare-earth elements, but for the dielectric behavior of their oxide the substitution of a fraction of the hafnium with zirconium and appropriate treatments can make the oxide ferroelectric.
Many great applications have been proposed for ferroelectric Hf-Zr dioxide already for some years, but I have not heard of any commercial device. The reason is not any compatibility problem with CMOS processes, but I believe that it might be hard to obtain reproducible ferroelectric properties, as they might vary a lot depending on the exact parameters of the manufacturing steps.
ok, let's see it in a real-world production environment. What works in the lab doesn't always scale to the factory floor.
It's not an uninteresting thing (it's very interesting, from a purely technical POV) but it reads like so many "groundbreaking" press releases that never materialize
> HZO is a ferroelectric. That is, it has a crystal structure that allows it to maintain an internal electrical field even when no external voltage is applied. (Conventional dielectrics don’t have this inherent electrical field.) When a voltage is applied to the transistor, HZO’s inherent electric field opposes it. In a transistor, this leads to a counterintuitive effect: A decrease in voltage causes an increase in the charge stored in HZO. This negative capacitance response effectively amplifies the gate control, helping the transistor’s 2D electron cloud accumulate charge and boosting the on-state current.
> Leakage current is a well-known problem in these kinds of transistors, “so integrating an innovative ferroelectric layer into the gate stack to address this has clear promise,” says Aaron Franklin, an electrical engineer at Duke University, in Durham, N.C. “It certainly is an exciting and creative advancement.”
I'm wondering if this will eventually transition out of power electronics into other sorts of electronics. Sounds like they've got their next five years planned just looking at power electronics though.
Negative capacitance in a field effect transistor is not new. In fact this has been shown mire than a decade ago. The reason it won't make its way into modern chips is because the materials used to make the ferroelectrics aren't CMOS foundry compatible.
Hafnium and zirconium dioxide are CMOS foundry compatible.
Hafnium dioxide has been the gate dielectric for MOS transistors in all dense CMOS processes for a couple of decades. It is certainly used in whatever smartphone or computer you have.
With the former gate dielectric, silicon dioxide, it was impossible to make MOS transistors as small as in modern processes, because it has a too low dielectric constant, which would have required impossibly thin gate layers (for high enough gate capacitances).
Hafnium dioxide has a much higher dielectric constant, allowing to achieve the same gate capacitance at a manageable gate thickness.
The chemical behaviors of hafnium and zirconium are almost identical, their similarity being as great as between rare-earth elements, but for the dielectric behavior of their oxide the substitution of a fraction of the hafnium with zirconium and appropriate treatments can make the oxide ferroelectric.
Many great applications have been proposed for ferroelectric Hf-Zr dioxide already for some years, but I have not heard of any commercial device. The reason is not any compatibility problem with CMOS processes, but I believe that it might be hard to obtain reproducible ferroelectric properties, as they might vary a lot depending on the exact parameters of the manufacturing steps.
Found some explanation what negative capacitance is:
https://electronics.stackexchange.com/questions/611003/what-...
ok, let's see it in a real-world production environment. What works in the lab doesn't always scale to the factory floor.
It's not an uninteresting thing (it's very interesting, from a purely technical POV) but it reads like so many "groundbreaking" press releases that never materialize