Fujitsu Corporation

Hideaki Ishikawa

Shunichi Muto

Toshio Fujii

Atsushi Takeuchi

Yoshihiro Sugiyama

Eizo Miyauchi

A method of fabricating a semiconductor device having an epitaxial layer of a group III-V semiconductor material provided on an underlying crystal layer with a lattice matching therewith, the semiconductor material being doped to the p-type by addition of beryllium and selected from a group including gallium aluminum arsenide and indium gallium aluminum arsenide, in which the method comprises steps of growing the epitaxial layer on the underlying crystal layer, adding beryllium to a concentration level of about 5.times.10.sup.19 atoms/cm.sup.3 to about 5.times.10.sup.20 atoms/cm.sup.3 to the semiconductor material, and adding indium by an amount of about 0.5 mole percent to about 8 mole percent with respect to group III elements in the semiconductor material.

Method of fabricating a heterojunction bipolar transistor

A non-linear semiconductor optical device comprises a first quantum well layer having discrete quantum levels of carriers including a first quantum level for electrons and a second quantum level for holes with an energy gap corresponding to a wavelength of an incident optical beam; a pair of barrier layers provided above and below the first quantum well layer in contact therewith with a thickness that allows a tunneling of the carriers therethrough for defining a potential well in correspondence to the first quantum well layer; and a second quantum well layer provided in contact with the barrier layers for accepting the carriers that have been created in the first quantum well layer upon excitation by the incident optical beam and escaped therefrom by tunneling through the barrier layer. The second quantum well layer comprises a material that has a conduction band including therein a .GAMMA. valley and an X valley, wherein said .GAMMA. valley is located at an energy level substantially higher than the first quantum level while said X valley is located at an energy level substantially lower than the first quantum level.

Non-linear quantum semiconductor optical device having a signal-to-noise

In an optosemiconductor device including a superlattice configuration (TBQ) of first and second quantum well layers and a potential barrier therebetween, photo-excited carriers are formed in the first quantum well layer and are tunnelled through the potential barrier toward the second quantum well layer, so that the tunneled carriers are accumulated in the second quantum well layer. An electric field is applied to the superlattice configuration to expel the tunneled carriers from the second quantum well layer.

Growing community of inventors

Hadano, Japan

Hideaki Ishikawa