Hi all, would it be possible to manufacture following structures in the sky130 process? It was reported that the structures CMUT were made in UMC 180 nm one-polysilicon six- metal (1P6M) CMOS process.

They used postprocessing for release after running it through UMC. In other words, this final structure was not made by UMC, and you can't make it with Sky130 unless you have a way to do the postprocessing.

Thank You @Boris Murmann, I supposed that they used some custom processing to release the inner layer. By the way what do You think about the idea of open sourcing MEMS technology, it seems to be much less popular than standard CMOS

Yes, it will take a while. Would have to convince some players like xfab to open their PDK: https://europractice-ic.com/technologies/mems/x-fab/

A time ago I found some useful information about MEMS technology published by Support Center for Microsystems Education in US. They have had some NSF founding for outreach activities in this field. Unfortunately their webpage seems to be down. https://www.scme-nm.org

There have been various efforts like this since the 1990s, but it has been too much of a niche outside volume products like gyros and accelerometers.

In fact difficult to compare, however each day much more visible.