Abstract: A high electron mobility transistor is disclosed which has a triple-layered main semiconductor region formed on a silicon substrate via a multilayered buffer region. The multilayered buffer region is in the form of alternations of an aluminum nitride layer and a gallium nitride layer. Whilst the aluminum nitride layers are of n-like conductivity, the gallium nitride layers are doped into p-type conductivity, with the consequent creation of pn junctions between the two kinds of buffer layers. Another pn junction is formed between one p-type gallium nitride layer and the adjoining n-like electron transit layer included in the main semiconductor region. The pn junctions serve for reduction of current leakage.

Abstract: A high electron mobility transistor is disclosed which has a triple-layered main semiconductor region formed on a silicon substrate via a multilayered buffer region. The multilayered buffer region is in the form of alternations of an aluminum nitride layer and a gallium nitride layer. Whilst the aluminum nitride layers are of n-like conductivity, the gallium nitride layers are doped into p-type conductivity, with the consequent creation of pn junctions between the two kinds of buffer layers. Another pn junction is formed between one p-type gallium nitride layer and the adjoining n-like electron transit layer included in the main semiconductor region. The pn junctions serve for reduction of current leakage.

Abstract: An LED is disclosed which has a laminated semiconductor body with an anode and a cathode formed on a pair of opposite faces thereof. Among the layers of the semiconductor body are an active layer of AlGaInP semiconductor material, an n type cladding layer of either n type AlGaInP or n type AlInP semiconductor material on one side of the active layer, and a p type cladding layer of p type AlGaInP or p type AlInP semiconductor material on another side of the active layer. Unlike the conventional belief that the active layer should be as free as possible from the infiltration of Zn used in the p type cladding layer as an impurity to determine its p conductivity type, and hence as high in crystallinity as possible, Zn is positively doped into the active layer with a concentration of 1.times.10.sup.16 -5.times.10.sup.17 cm.sup.-3.