| 摘要 |
PURPOSE:To reduce the variations of carrier distribution in a channel layer, by a method wherein ion implantation is carried out through an AlN film on a single crystal GaAs substrate, and an insulating film is formed on the film, and then a heat treatment is carried out. CONSTITUTION:An AlN film 2 is formed on a single crystal GaAs substrate 1. A mask 3 having an opening corresponding to a region in which a channel layer is to be formed is formed on the film 2. Ion implantation is carried out to form a channel layer 4. After the mask 3 is removed, an insulating film, preferably an AlN film 5 is formed again. A heat treatment is carried out to activate the implanted ions. This method makes it possible to reduce the number of defects and adverse effects generated in the ion implantation and the heat treatnemt carried out thereafter and to uniform the carrier distribution in the channel layer, thereby to lessen the variations in threshold voltage between FETs formed on the substrate 1.
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