Abstract: A high response speed semiconductor photo detecting device having a thin photo absorption layer which avoids an optical efficiency loss. The semiconductor photo detecting devices are formed on a semiconductor substrate having an inclined cleavage face to a principal plane of the substrate. An incoming photo signal is input to the cleavage face perpendicularly.

Abstract: A high response speed semiconductor photo detecting device having a thin photo absorption layer which avoids an optical efficiency loss. The semiconductor photo detecting devices are formed on a semiconductor substrate having an inclined cleavage face to a principle plane of the substrate. An incoming photo signal is input to the cleavage face perpendicularly.

Abstract: An avalanche photodiode comprises a substrate, a first semiconductor layer provided on the substrate and made of a first group III-V compound semiconductor material doped to a first conductivity type for producing carriers in response to optical radiation incident to the avalanche photodiode, a second semiconductor layer provided on the first semiconductor layer and comprising a second group III-V compound semiconductor material doped to the first conductivity for causing an avalanche multiplication of the carriers, a photoreception region formed within the second semiconductor layer and doped to a second conductivity type for forming a p-n junction at an interface to the second semiconductor layer, and a guard ring formed along a lateral boundary of the photoreception region.

Abstract: An avalanche photodiode sensitive to a wavelength range of from 1.2 to 1.65 micrometers is provided with a light absorbing layer, a middle layer and an active layer grown in order, on a substrate. All the layers contain impurities with the same conductivity but the impurity concentration is higher in the middle layer than in either of the light absorbing layer and the active layer. A p-n junction having a flat bottom and either a gradually inclined side or a step-shaped side is produced in the active layer, so that the breakdown voltage is made much less in the area facing the flat bottom of the p-n junction than in the area facing a side which has the aforementioned irregular shape. As a result, the side acts as a guard ring without being accompanied by a large amount of tunnel current flowing through the light absorbing layer in response to the intensity of the electric field.

Abstract: A semiconductor device, and a method for manufacturing it in which ions of beryllium are implanted into a germanium substrate to form a layer containing p-type impurity material. There after the substrate is heated at a temperature in the range of 400.degree. C. to 700.degree. C. to diffuse the beryllium ions into the substrate so that the concentration of beryllium at the surface of the impurity layer is in the order of 10.sup.17 cm.sup.-3 or more. In one embodiment, a p-type channel stopper is formed locally in a p-type germanium substrate and an n-type active layer is formed in a region surrounded by, and isolated from, the channel stopper region. In another embodiment, a relatively shallow p-type active layer is formed at one part of an n-type germanium substrate and p-type guard ring regions are formed surrounding, and partly overlapping said p-type active layer.