Abstract A semiconductor laser device having an enclosed laser cavity is disclosed. The semiconductor laser is of the heterostructure type and embodiments of single and double heterostructures are disclosed. In both of the heterostructure devices disclosed, the side surfaces of the active region are well defined. This is accomplished, in one instance, by surrounding the laser active region on all side surfaces with a higher band gap material which also has a lower index of refraction. Thus, the laser cavity is partially enclosed by a semiconductor material on one conductivity type of a band gap higher than the band gap of the material of the laser cavity. The remaining portion is enclosed by a band gap material higher than the material of the laser cavity but is of opposite conductivity type to the first mentioned higher band gap material. In another instance the side surfaces of the laser active region are partially surrounded by a high band gap material and partially by a region of opposite conductivity type to the active region; both of which regions contribute carriers to the active region. The laser devices disclosed are made, for example, from layers of appropriately doped P and N type gallium arsenide and from layers of P and N type gallium aluminum arsenide. The resulting devices can have very small cavity cross sections, optical and electrical confinement of the excitation at all the side surfaces, low electrical series resistance and a low thermal resistance due to geometrical factors. The laser devices disclosed may be fabricated using well known fabrication techniques which include deposition of the layers of the laser by liquid phase epitaxy (LPE), molecular beam epitaxy (MBE) and melt-back or etching techniques. The latter techniques define the laser cavity.
A SEMICONDUCTOR LASER COMPRISING: A SUBSTRATE OF P TYPE CONDUCTIVITY GALLIUM ARSENIDE, A FIRST LAYER OF P TYPE CONDUCTIVITY GALLIUM ALUMINUM ARESNIDE DISPOSED ON SAID SUBSTRATE, A SECOND LAYER OF N TYPE CONDUCTIVITY GALLIUM ALUMINUM ARSENIDE DISPOSED ON SAID FIRST LAYER, A THIRD LAYER OF N TYPE CONDUCTIVITY GALLIUM ARSENIDE DISPOSED ON SAID SECOND LAYER FORMING WITH SAID SECOND LAYER A NN HETEROJUNCTION, A FOURTH LAYER OF N TYPE CONDUCTIVITY GALLIUM ALUMINUM ARSENIDE DISPOSED ON SAID THIRD LAYER FORMING WITH SAID THIRD LAYER A NN HETEROJUNCTION, A REGROWN REGION OF P TYPE CONDUCTIVITY GALLIUM ALUMINUM ARSENIDE INTERSECTING A PORTION OF SAID SUBSTRATE AND EACH OF SAID LAYERS FORMING WITH SAID THIRD LAYER A PP HETEROJUNCTION, A DIFFUSION FRONT EMANATING FROM SAID REGROWN REGION FORMING WITHIN A PORTION OF SAID THIRD LAYER A P TYPE CONDUCTIVITY REGION SAID FRONT FORMING WITH SAID THIRD LAYER A PN HOMOJUNCTION.
Claim 2
Dependent Claim
146 words
A SEMICONDUCTOR LASER COMPRISING: A SUBSTRATE OF P TYPE CONDUCTIVITY GALLIUM ARSENIDE, A FIRST LAYER OF P TYPE CONDUCTIVITY GALLIUM ALUMINUM ARESNIDE DISPOSED ON SAID SUBSTRATE, A SECOND LAYER OF N TYPE CONDUCTIVITY GALLIUM ALUMINUM ARSENIDE DISPOSED ON SAID FIRST LAYER, A THIRD LAYER OF N TYPE CONDUCTIVITY GALLIUM ARSENIDE DISPOSED ON SAID SECOND LAYER FORMING WITH SAID SECOND LAYER A NN HETEROJUNCTION, A FOURTH LAYER OF N TYPE CONDUCTIVITY GALLIUM ALUMINUM ARSENIDE DISPOSED ON SAID THIRD LAYER FORMING WITH SAID THIRD LAYER A NN HETEROJUNCTION, A REGROWN REGION OF P TYPE CONDUCTIVITY GALLIUM ALUMINUM ARSENIDE INTERSECTING A PORTION OF SAID SUBSTRATE AND EACH OF SAID LAYERS FORMING WITH SAID THIRD LAYER A PP HETEROJUNCTION, A DIFFUSION FRONT EMANATING FROM SAID REGROWN REGION FORMING WITHIN A PORTION OF SAID THIRD LAYER A P TYPE CONDUCTIVITY REGION SAID FRONT FORMING WITH SAID THIRD LAYER A PN HOMOJUNCTION.
Claim 3
Dependent Claim
19 words
A semiconductor laser according to claim 1 further including metallic contacts connected to said substrate and said fourth layer.