| 摘要 |
PURPOSE:To improve yield, to enhance uniformity in a surface of electric characteristics and to increase thermal stability in a manufacturing process for an element by using a reference regulating the quantity of carbon added within a specific range in order to semi-insulating a gallium arsenide crystal for the semi-insulating substrate. CONSTITUTION:Carbon 4 forming a shallow acceptor unit is added to the crystal in place of the addition of an impurity forming a narrow level capturing excessive electrons 1 in order to manufacture a semi-insulating crystal. Excessive electrons are captured by the levels 4 of carbon, residual carbon discharges holes 5 to a filled band, and the crystal is changed into a p type. On the other hand, there are several deep endogenous donor levels 6 in the gallium arsenide crystal through melting-liquid growth, and the crystal is changed into semi-insulating property because the levels 6 capture the holes. When the total of the concentration of a shallow donor impurity 2 is Nd, the total of the concentration of a shallow acceptor impurity 3 Na, the concentration 4 of carbon added Nc and the concentration of the deep donor levels 6 of highest concentration NDD, the quantity of carbon to be added 4 is shown in the following conditions. Nd-Na< Nc<NDD+Nd-Na. |
