Method of manufacturing a semiconductor device

Claim 1

In a method of manufacturing a semiconductor device, the method comprising the steps of providing a monocrystalline substrate in a deposition chamber of a molecular beam epitaxy apparatus, reducing pressure in the deposition chamber to below atmospheric pressure, heating the substrate, causing a plurality of successive combinations of molecular beams to be indicident on the substrate so as to form a plurality of epitaxial layers, wherein the molecular beams each comprise a constituent element of the respective layer material and each beam emanates from a separate source when a shutter associated with the respective source has been opened, the improvement comprising the steps of increasing the rate of input of heat to that source when the shutter of that source is opened, said increase being of a predetermined value so that the temperature of that source does not change substantially as a result of the opening of the shutter, and reducing the rate of input of heat to that source when the said shutter is closed, said reduction being of said predetermined value.

Claim 5

A method as claimed in claims 3 - 4, wherein the rate of input of heat to a source is controlled by a four function controller in which the fourth function is linked to means controlling the opening and closing of the shutter associated with that source, and the fourth function produces the predetermined increase in rate of input of heat to the source.

Claim 6

A method as claimed in any of claims 1 to 3, wherein said rate of input of heat to each source and the opening and closing of the shuttes are controlled by means of a microprocessor or a microcomputer.