| 摘要 |
PURPOSE:To selectively obtain intensive light emission only in a region of arbitrary depth, by locally or uniformly introducing ions of high electronegativity in a silicon substrate, by using an ion implantation method. CONSTITUTION:Oxygen ions 2 are implanted in a P-type silicon substrate 1 doped with boron, under the condition of the kinetic energy of 4MeV and the density of 1X10<15>ions/cm<2>. An anode composed of the silicon substrate 1 and a cathode composed of a platinum electrode 5 are dipped in hydrofluoric acid solution 6 in a reaction cell. The volume ratio of the solution is HF:H2O=1:1. When a current whose density is 20mA/cm<2> is made to flow for about 13 minutes between the anode and the cathode, electrochemical reaction is generated, and a porous silicon layer 31 having different hole diameters are formed in the region where oxygen in the surface layer of the P-type silicon substrate 1 distribute with high density. Hence the surface of the porous silicon light- emitting layer is not terminated by hydrogen but by ions of high electronegativity. Thereby a light-emitting layer wherein deterioration of luminous intensity caused by light irradiation is little can be obtained. |
