TECHNIQUES FOR ELECTRICALLY ISOLATING N AND P-SIDE REGIONS OF A SEMICONDUCTOR LASER CHIP FOR P-SIDE DOWN BONDING
In general, a MQW semiconductor laser chip with an electrically insulated P-side region and a process for forming the same is disclosed. The MQW semiconductor laser chip, also referred to herein as a MQW semiconductor laser or simply a semiconductor laser, includes a layer of electrically insulative material that extends along at least a portion of the sidewalls to minimize or otherwise reduce the potential for electrical shorts between P and N-sides of the same when utilizing P-side bonding techniques.
1 . A semiconductor laser chip, the semiconductor laser chip comprising:
a substrate formed of a first semiconductor material;
a cladding layer formed of an N-type material disposed on the substrate;
a first layer of metallic material disposed on a first end of the substrate to provide an N-side metal contact in electrical communication with the cladding layer of the N-type material;
a multi quantum well (MQW) disposed adjacent a second end of the substrate;
a first layer of electrically insulative material disposed on the second end of the substrate;
a second layer of metallic material disposed on the second end of the substrate to provide a P-side metal contact in electrical communication with the MQW; and
wherein the layer of electrically insulative material is disposed on at least a portion of the second end of the substrate and on a first sidewall of the substrate, the sidewall adjoining the first and second ends of the substrate.
2 . The semiconductor laser chip of claim 1 , wherein the first sidewall defines a first notch that extends from the second end towards the first end, and wherein the first layer of electrically insulative material is disposed on the notch.
3 . The semiconductor laser chip of claim 2 , wherein the substrate further includes a second sidewall that adjoins the first and second ends, and wherein the second sidewall defines a second notch.
4 . The semiconductor laser chip of claim 3 , further comprising a second layer of electrically insulative material disposed on the second end of the substrate and the second notch.
5 . The semiconductor laser chip of claim 1 , wherein the substrate comprises a III-V semiconductor material.
6 . The semiconductor laser chip of claim 1 , wherein the N-type material comprises gallium arsenide (GaAs) or indium phosphide (InP).
7 . The semiconductor laser chip of claim 1 , wherein the MQW comprises a buried heterostructure.
8 . The semiconductor laser chip of claim 1 , wherein the electrically insulative layer is an oxidation passivation layer comprising silicon dioxide (SiO2) or silicon nitride.
9 . The semiconductor laser chip of claim 1 , wherein the second end of the substrate defines first and second channels, and wherein the MQW is disposed between the first and second channels.
10 . The semiconductor laser chip of claim 1 , implemented as an infrared laser capable of emitting channel wavelengths of 1300 nm to 1700 nm.
11 . An optical subassembly module for transmitting at least one channel wavelength, the optical subassembly module comprising:
a printed circuit board;
a laser arrangement including at least one multi quantum well (MQW) semiconductor laser coupled to the printed circuit board, the at least one MQW semiconductor laser having a P-side region at a first end and an N-side region at a second end, and a plurality of sidewalls adjoining the first and second ends, and wherein at least one layer of electrically insulative material is disposed on the P-side region of the second end and at least partially along the plurality of sidewalls; and
solder material disposed between the at least one MQW semiconductor laser and the printed circuit board, and wherein the at least one layer of electrically insulative material disposed at least partially along the plurality of sidewalls of the MQW semiconductor electrically insulates the N-side region from electrically shorting with the solder material.
12 . The optical subassembly module of claim 11 , wherein the at least one MQW semiconductor laser comprises at least one notch along the plurality of sidewalls, and wherein the at least one layer of electrically insulative material is disposed on the notch.
13 . The optical subassembly module of claim 12 , wherein the notch is formed at least partially as a V-groove.
14 . The optical subassembly module of claim 11 , wherein the P-side region has an overall thickness that is less than the N-side region.
15 . The optical subassembly module of claim 11 implemented as a multi-channel optical transceiver capable of transmitting and receiving at least four different channel wavelengths.