| 摘要 |
PURPOSE:To improve the characteristic of a junction type FET formed by ion implantation by adding one of Mg, Be and Zn to a half-insulating substrate in an amount almost equal to that of electrically active Si. CONSTITUTION:Taking account of variations with methods of growing substrates, growth requirements and the like, the amount of Si contained in a half-insulating substrate is determined at a constant value. A P type impurity other than Cr is contained in a melted liquid for forming a substrate in the amount equivalent to the amount of Si to form a substrate. This compensates for Si to concel the possible effect thereby steeping the last transition of the electronic concentration distribution. In other words, Mg is added to a Cr-added CaAs melted liquid which contains the known amount of electrically active Si in the amount almost equivalent to that of Si and then, pulled up. After a mirror finish grinding, Si<+> is implanted into the mixture to make an N layer 12 and further, Si<++> is selectively implanted to make N<+> type source and drain 13 and 14. Then, a heat treatment can highly speed the electronic concentration of the interface between the substrate and the layers 12-14 while enabling the even formation of the interface with a good reproductivity, thus especially improving the gain remarkably. Besides Mg, Be and Zn are effective. |
