| 摘要 |
PURPOSE:To make a compound semiconductor substrate having a high resistance to have a low resistance by a method wherein ion implantation is performed after the substrate is heated in a gas atmosphere containing the constituting element. CONSTITUTION:In the semi-insulating compound semiconductor substrate, plural impurities from deep impurity levels, and the activation ratio of an ion implanted impurity by heat treatment is small. Moreover the mobility of the activated carrier is reduced because the mobility is compensated by the impurities having deep levels. Therefore, for example, a GaAs semi-insulating substrate is heated in the atmospher containing As for a prescribed time. At the time shorter than this, impurities having deep levels exist in the active low resistance region to reduce the mobility of carriers, and at the longer time, the resistivity of the interface against the semi-insulating substrate is reduced to generate leak. An adequate partial pressure of As prevents both of the discharge of As from the substrate by heating and the generation of defect. After then by ion implanting S, etc., as usual and performing the prescribed activation by heating, the resistance can be reduced and both of the activation ratio and the mobility can be elevated. |
