SSM - Solid State Microtechnologies by solid state music
In what Synths?
List of SSM in Synths 
after the death of Doug Curtis there are a number of clones available by ALFA and Behringer/Music Tribe under the brand of "Cool Audio". There is also: "Sound Semiconductor" OnChip - is the last one remaining after SSM/Curtis as the old one - strangly. atm it is easy to pick up one of the first 3 right now - ALFA has them for about 7€ per item which makes it totally possibly to make analog (poly)synths again in 2018 and later.