| 摘要 |
<p>PURPOSE:To improve the switching function by enhancing the junction areas of a base and a graft base by utilizing a difference in diffusion speed of Zn between two materials, InP and InGaAsP when using these as crystal materials. CONSTITUTION:The crystal plane is covered with SiO2, Si3N4 or the like selectively and an InP layer 102, an InGaAsP 103, and an InP layer 104 are etched to reach a semiconductor substrate 101 by use of an etchant of chlorine or bromine group. After a cleaning process, crystal growth is made in the etched part selectively to form a semiconductor layer 105. In this case, for example, Zn is used for a P type impurity of the semiconductor layer 105 and the concentration of carriers is determined higher than in the semiconductor layers 102, 103, and 104. Consequently, Zn is autodoped into the semiconductor layers 102, 103 and 104 by heating at crystal growth of the semiconductor layer 105. At this time, the diffusion speed of Zn is extremely slower in InGaAsP than in InP so that the autodoped diffusion front becomes as designated by a dotted line in the figure.</p> |
