Thanks Tim! how to go about fixing this in the dev gen?

Repo https://github.com/RTimothyEdwards/open_pdks file

sky130/magic/sky130.tcl

lines 6829 and following define how to draw the SONOS device. This is really just the standard MOSFET drawing routine with a few different dimensions:

proc sky130::sky130_fd_bs_flash__special_sonosfet_star_draw {parameters} {
    set newdict [dict create \
            gate_type           nsonos \
            diff_type           ndiff \
            diff_contact_type   ndc \
            plus_diff_type      psd \
            plus_contact_type   psc \
            poly_type           poly \
            poly_contact_type   pc \
            sub_type            psub \
            id_type             dnwell \
            id_surround         1.355 \
            min_effl            0.185 \
            min_allc            0.26 \
    ]
    set drawdict [dict merge $sky130::ruleset $newdict $parameters]
    return [sky130::mos_draw $drawdict]
}

It presumably needs a value added to

newdict

gate_to_diffcont   <something> \

The default is 0.145 (see line 61), so you need to measure the amount by which the device is in error and add that to 0.145 and it should then be drawn correctly.

Thanks! will try that

If you get it to work, send a diff file or a pull request.