So, over 50 years ago, starts a story in Electronics Weekly's edition of April 19th 1961.
The story continues:
Visiting the Gem Mill and Wythenshawe works of Ferranti recently, I was told work is proceeding at high speed on epitaxial techniques, and the wafers of material are being produced by Ferranti in their own plant.
Epitaxial layers are being deposited at the rate of one micron per minute, and it was stated that a sufficiently high rate of production to meet demands could be maintained.
Work on epitaxy began at Ferranti's early in 1960l.
Work on planar devices is not so advanced but progress is being made.