| 摘要 |
PURPOSE:To increase the mobility of secondary electron gas by storing the gas in the first semiconductor layer of the secondary electron supply source and the second semiconductor layer for forming a well type potential interposed by high resistance layers. CONSTITUTION:A non-impurity-added Al0.3Ga0.7As spacer layer 21 of approx. 60Angstrom thick formed on an N<+> type Al0.3Ga0.7As layer 4 of the first semiconductor layer, a non-impurity-added Al0.5Ga0.5As layer 22 as a high resistance layer of approx. 200Angstrom thick formed on an undoped GaAs layer 6 of the second semiconductor layer, an N<+> type Al0.5Ga0.5As layer 23 as the third semiconductor layer of approx. 200Angstrom thick added with 2X10<18>cm<-3> of Si formed on the layer 22, and an N<+> type GaAs layer 24 of approx. 300Angstrom added with 2X10<18>cm<-3> of Si formed on the layer 23 for reducing a surface potential and inactivating the surface are formed. |
