Source: http://www.google.com/patents/US4852111?ie=ISO-8859-1
Timestamp: 2014-08-30 05:40:56
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Matched Legal Cases: ['application No. 57', 'application No. 57', 'application No. 59', 'application No. 59', 'application No. 58', 'application No. 58']

Patent US4852111 - Semiconductor laser device - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign in<nobr>Advanced Patent Search</nobr>PatentsA semiconductor laser device comprising a substrate of a first conductivity type having a mesa; a first semiconductor layer of a second conductivity type which is formed on the upper surface of the substrate other than the mesa to form a flat plane including the top face of the mesa; a laser oscillation...http://www.google.com/patents/US4852111?utm_source=gb-gplus-sharePatent US4852111 - Semiconductor laser deviceAdvanced Patent SearchPublication numberUS4852111 APublication typeGrantApplication numberUS 07/132,300Publication dateJul 25, 1989Filing dateDec 15, 1987Priority dateDec 15, 1986Fee statusPaidAlso published asDE3778510D1, EP0272096A2, EP0272096A3, EP0272096B1, US4907239Publication number07132300, 132300, US 4852111 A, US 4852111A, US-A-4852111, US4852111 A, US4852111AInventorsToshiro Hayakawa, Takahiro Suyama, Kosei Takahashi, Masafumi KondoOriginal Assignee501 Sharp Kabushiki KaishaExport CitationBiBTeX, EndNote, RefManPatent Citations (19), Non-Patent Citations (12), Referenced by (11), Classifications (6), Legal Events (4) External Links: USPTO, USPTO Assignment, EspacenetSemiconductor laser deviceUS 4852111 AAbstract A semiconductor laser device comprising a substrate of a first conductivity type having a mesa; a first semiconductor layer of a second conductivity type which is formed on the upper surface of the substrate other than the mesa to form a flat plane including the top face of the mesa; a laser oscillation region which is formed on the flat plane and includes an active area for laser oscillation; and a multi-layer structure burying the laser oscillation region, the multi-layer structure comprising a high resistance layer formed on the first semiconductor layer and burying both sides of the laser oscillation region, and a second semiconductor layer of the first conductivity type formed on the high resistance layer.
What is claimed is: 1. In a semiconductor laser device comprising:a substrate of a first conductivity type having a mesa; a first semiconductor layer of a second conductivity type which is formed on the upper surface of said substrate other than said mesa to form a flat plane including the top face of said mesa; a laser oscillation structure comprising a first cladding layer, a first GRIN layer, a second GRIN layer, and a second cladding layer, which is formed on said flat plane and includes an active area for laser oscillation between said first and second GRIN layers and above said mesa; and a multi-layer structure burying said laser oscillation structure, said multi-layer structure comprising a high resistance layer formed on said first semiconductor layer and burying both sides of said laser oscillation structure, and a second semiconductor layer of the first conductivity type formed on said high resistance layer. 2. A semiconductor laser device according to claim 1, wherein said active area comprises quantum well layers.
SUMMARY OF THE INVENTION The semiconductor laser device of this invention, which overcomes the above-discussed and numerous other disadvantages and deficiencies of the prior art, comprises a substrate of a first conductivity type having a mesa, a first semiconductor layer of a second conductivity type which is formed on the upper surface of said substrate other than said mesa to form a flat plane including the top face of said mesa, a laser oscillation region which is formed on said flat plane and includes an active area for laser oscillation and a multi-layer structure burying said laser oscillation region, said multi-layer structure comprising a high resistance layer formed on said first semiconductor layer and burying both sides of said laser oscillation region, and a second semiconductor layer of the first conductivity type formed on said high resistance layer.
DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the invention, the semiconductor laser device comprises the substrate of the first conductivity type having the mesa and the first semiconductor layer of the second conductivity type burying the steps of the substrate formed by the mesa, and the top face of the mesa and the surface of the first semiconductor layer form a flat plane, thereby enabling the formation of the laser oscillation region on the flat plane by MBE or MOCVD.
EXAMPLE FIGS. 1A to 1D show the steps of producing one example of the semiconductor laser device of the invention, and FIG. 2 shows a cross sectional view of the device. Referring to FIGS. 1A to 1D and 2, the production process and structure of the example will be described.
The surface of a p-GaAs substrate 11 is etched to form a stripe mesa 20 having a width of 1 μm and a height of 2 μm. On the substrate 11, an n-GaAs current blocking layer 12 (Te=2�1018 cm-3) is grown so that the mesa 20 is buried (FIG. 1A).
As shown in FIG. 1C, on the flat plane, a p-Al0.7 Ga0.3 As cladding layer 13 (Be=1�1018 cm-3 ; the thickness thereof being 1 μm), an undoped Alx Ga1-x As GRIN layer (optical guiding layer) 14 (the thickness thereof being 0.2 μm), an undoped GaAs quantum well layer (active area) 15 (the thickness thereof being 70 Å), an undoped Alx Ga1-x As GRIN layer (optical guiding layer) 16 (the thickness thereof being 0.2 μm), an n-Al0.7 Ga0.3 As cladding layer 17 (Si=1�1018 cm-3 ; the thickness thereof being 1 μm), and an n-Al0.05 Ga0.95 As cap layer 18 (Si=1�1018 cm-- ; the thickness thereof being 0.05 μm) are successively grown by MBE. In this example, the AlAs mole fraction x of the GRIN layers 14 and 16 is parabolically changed in the range of 0.2 to 0.7. Namely, the AlAs mole fraction of the GRIN layers 14 and 16 increase parabolically with distance from the quantum well layer 15.
Thereafter, an undoped Al0.8 Ga0.2 As burying layer 21 (0.1 Ω. cm or more), a p-Al0.8 Ga0.2 As burying layer 22 (Mg=1�1018 cm-3), and a n-GaAs cap layer 23 (Te=1�1018 cm-3) are successively grown by LPE so as to bury the mesa-shaped laser oscillation region. Both sides of the quantum well layer (active area) 15 are fully buried by the high resistance layer 21. Then, Au-Zn and Au-Ge/Ni are deposited on the back face of the n-GaAs substrate 11 and the upper face of the cap layer 23, respectively, and an alloy treatment is conducted to form ohmic p-sided and n-sided electrodes 31 and 32, resulting in a semiconductor laser device.
1.5 mA-(360 A/cm2 �1 &#956;m �250 &#956;m)=0.6 mA
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