| 摘要 |
PURPOSE:To make the tail portions of a density distribution semi-insulative and avoid the leakage of electric current by specifying a donor impurity density which produces conduction electrons as well as an acceptor imprurity density that makes semiconductor layer semi-insulative and perform doping. CONSTITUTION:In the case of BH laser that makes buried semiconductor lasers 6 semi-insulative, a density distribution of acceptor impurity that performs thermal diffusion from a p<+> contact layer 5 and p-type confinement layer 4 to the buried layers 6 is composed of a shallow high density area 7s that is confined within the vicinity of interface and an area 7t of low density distribution that is called tail of its area and is deeper than 7s and yet above density distribution permits most of leaked electric current IL to flow through the railed area 7t. Thus, on the occasion of epitaxial growth of the buried semiconductor layers that are in a semi-insulative state, a relation between a maximum density Na in the area of 7t of the density distribution of diffused acceptor impurities and a density Nd of donor impurities that develop conduction electrons is shown by Nd.Na and further, the relation between the above Nd and an acceptor impurities density Nt that forms deeper level is shown by Nt>Nd. The above state causes the conduction electrons in all areas including ranges that are not under the influence of acceptor impurities thermal diffusion to be in a semi-insulative area by trapping. |
