How to use isolated 1.8V nfet transistor in design with sky130 pdk? There is no dedicated symbol available for isolated NMOS device nor layout pcell. Please suggest what is the best approach to use this device in design. @Mitch Bailey @Luis Henrique Rodovalho

You must use deep n wells. There's a menu option to create them in magic. You can create them manually also. Just remember that you must bias the transistor isolated pwell substrate with a tap, and the same for the nwell guard ring connected to the deep nwell, and the common p-substrate.

Thank @Luis Henrique Rodovalho Is this correct way for layout of isolated nfet ? What about symbol for this iso nmos. Will any separate symbol required in schematic.

@vks Do you have deep nwell and nwell there? I can’t tell if you’re using the default layer styles or not.

What about symbol for this iso nmos.

There is no dedicated symbol for the isolated nmos. The deep nwell connection is not included in the simulation model. Just use the same symbol that you’d use without the deep nwell.

@Mitch Bailey Dnwell was added to nfet layout using steps shown in attached recording. Hope it is correct way. And using symbol of normal 1.8 nfet will pass LVS ?

The new device generator should work for drawing deep nwell. The previous one filled the whole area with nwell and then deleted nwell in the middle. Unfortunately, this changed the device types. The newest device generator creates 4 separate nwell regions surrounding the isolated Pwell. It should pass LVS with normal nfets. Let me know if it doesn’t.