IGZO-TFT and its applications are patented by Japan Science and Technology Agency (JST). Patents have been licensed to Samsung Electronics (in 2011) and Sharp (in 2012) - and it seems that LG Display has joined them (but they produce IGZO panels only for Apple as far as I know).
Surface Pro 4 display unit is from Samsung: 12.3 inch 3:2, 2736x1824 pixel 267 PPI, 10-point multi-touch, Samsung 123YL01-001 ID: SDC3853, IPS
Sourcing the displays from Korea (info from one of Konstantino's posts) does point to Samsung and the same or similar display unit as on Surface Pro 4.
Samsung makes two displays units in 12,3 inch size and 2736 x 1824 resolution (part of specifications):
Information taken from: http://www.panelook.com/sizmodlist.php?sizes%5B%5D=1230
The listing on Panelook website doesn't exclude that there is some other display panel manufacturer that isn't on this list.