What is the zero Vt device?

[dongqing]

Hi all:

What is the zero Vt device? Vt = 0?

What is the usage?

Thanks

dongqing

 

[panditabupesh]

zero vt

Native device- could be used as MOSCAP.

Bupesh

 

[leohart]

zero vt device

What's the advantage of zero vt mos as moscap comparing to normal vt mos?

Added after 57 seconds:

Is it used as active device in analog or digital design?any advantage?

 

[protonixs]

native device leakage

is it the same wiht Vt-shift diode?

 

[srieda]

zero vt nmos

With a native device, the capacitance (C-V curve) is maximum already at Vgs=0. Thus no need to bias the device..

 

[ieropsaltic]

zero vt mosfet

A zero Vt device is a MOSFET device that has zero threshold voltage i.e it's normally on, it can be used for numerous applications. For analog circuits, it can be used as MOS capacitor. At MOS cap., we use the capacitance between the gate and the substrate to have a certain capacitance. This requires the MOSFET to be on. For usual MOSFETs, this requires biasing by making Vgs>Vt but for zero Vt devices, biasing is not required.

For digital circuits, 0-Vt MOSFETs can be used at transmission gates to deliver strong ones and zeros and to enable gates of MOSFETs of other transmission gates by a transmission gate logic output.

These devices however require an extra mask thus higher costs and suffer from higher leakage.

 

[rowokii]

low vt high vt

Humm... I was under the impression the native device was "free" in terms of not requiring an extra mask... at least on last few TSMC processes I've worked on. By default, MOSFET are all "native device" and they need an implant to raise the Vt to the normal level.

 

[psmon]

native nmos back bias

Zero Vt devices are good for low voltage operation...

 

[mdcui]

nmos zero vt

another application: using it as source follower can give you zero voltage drop, we use this sometimes for voltage clamping.

 

[dongqing]

0vt charge pump

Then it should be difficult to realize the zero vt device
need specific technology?
we use it very scarely , right ?

 

[piao]

charge pump zero vt mos

as mentioned above, just does not need the extra leayer, just need the foundry to provide the process file.


yes, it is used very scarely.

 

[waxtomato]

utilisation mos zero vt

for low voltage supply, the zero vt will help lose the limit of dynamic range; but be ware of the leakge, it it huge

 

[benariaa]

vt zero

Another usage for Native transistors is in LV (1V) circuits. Sub-micron devices start to have a noticeable gate leakage, in some case (such as the charge-pump input of a VCO) having a large leakage would cause instability, i.e. jitter. A good solution would be to put a Native 3.3V transistor – thus we can have high source while reducing the leakage drastically. The same can be applied to any other Voltage bias.

 

[dinlk]

zero+threshold+fet

A zero Vt device is a MOSFET device that has zero threshold voltage i.e it's normally on, it can be used for numerous applications. For analog circuits, it can be used as MOS capacitor. At MOS cap., we use the capacitance between the gate and the substrate to have a certain capacitance. This requires the MOSFET to be on. For usual MOSFETs, this requires biasing by making Vgs>Vt but for zero Vt devices, biasing is not required.

For digital circuits, 0-Vt MOSFETs can be used at transmission gates to deliver strong ones and zeros and to enable gates of MOSFETs of other transmission gates by a transmission gate logic output.

These devices however require an extra mask thus higher costs and suffer from higher leakage.

can u explane little bit more regarding
[For digital circuits, 0-Vt MOSFETs can be used at transmission gates to deliver strong ones and zeros and to enable gates of MOSFETs of other transmission gates by a transmission gate logic output.]

or any information source to know more?