Abstract: A capacitance diode has a substrate of a first conductivity type, an epitaxial layer of the first conductivity type present thereon, a first zone of the first conductivity type diffused therein and a second surface zone of the second opposite conductivity type over said first zone and forming a p-n junction with the first zone. According to the invention, the doping profile in the first zone varies substantially according to the equation N(x)=N.sub.o e.sup.-.beta.x +N.sub.E, where N.sub.o is the doping concentration of the first zone at the p-n junction, N is the doping concentration of the epitaxial layer, and x is the distance from the p-n junction, and where N.sub.o <24 N.sub.E. As a result, a small frequency deviation is obtained, and this frequency deviation does not change sign.

Abstract: A photosensitive semiconductor resistor has a monocrystalline semiconductor body of one conductivity type which, on two oppositely located surfaces, is provided with an anode contact and with a cathode contact, and is constructed so that the cathode contact is a highly doped zone of the same conductivity type as the semiconductor body. The semiconductor body can be exposed to photon radiation at its surface supporting the cathode contact and the area of the anode contact is at least 1000 times larger than the area of the cathode contact. Such a photosensitive semiconductor resistor is easy to manufacture and has both a low inertia and a good sensitivity.

Abstract: A capacitance diode includes an epitaxial layer of a first conductivity type provided on a substrate in which a doping profile is formed in the epitaxial layer by controlled doping during the epitaxial layer growth, and a surface zone of the second conductivity type which forms a p-n junction with the epitaxial layer. According to the invention, the doping profile in the epitaxial layer varies according to the equation ##EQU1## wherein x is the distance from the p-n junction in .mu.m, x.sub.o is the width of the barrier layer in .mu.m at a voltage -U.sub.D across the p-n junction, U.sub.D is the diffusion voltage of the p-n junction, and k, n and .beta. are constants. As a result of this doping profile, a very low frequency deviation is obtained which does not change sign.