# US 2010/0166360 A1 · Acid block for hybrid silicon device processing compatible with low-loss waveguides > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2010/0166360 A1 - Document ID: US20100166360A1 - Status: Published application - Kind: A1 - Application number: 12/346,779 - Filed: 2008-12-30 - Published: 2010-07-01 - Earliest claimed: 2008-12-30 - Inventors: Richard Jones; Alexander W. Fang - Web page: https://patentgrep.com/patent/US20100166360A1 ## CPC - G02B 6/122: Basic optical elements, e.g. light-guiding paths - G02B 6/136: by etching - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract An acid-stop structure for a rib waveguide comprises a fin structure formed between the sidewalls in each rib channel of the rib waveguide, thereby preventing acids and other etchants from flowing down the rib channel and under a die that has been bonded to a wafer. ## Claims ### Claim 1 A device, comprising: a waveguide comprising a rib structure between a first waveguide channel and a second waveguide channel, the first waveguide channel comprising a first sidewall and a second sidewall, the first sidewall of the first waveguide channel comprising a sidewall of the rib structure; and at least one fin structure formed between the first sidewall and the second sidewall of the first waveguide channel, the fin structure comprising a height that is substantially equal to a height of the first sidewall and the second sidewall. ### Claim 2 (depends on 1) The device according to claim 1, wherein the second waveguide channel comprises a first sidewall and a second sidewall, the first sidewall of the second waveguide channel comprising a sidewall of the rib structure, the device further comprising at least one fin structure formed between the first sidewall and the second sidewall of the second waveguide channel. ### Claim 3 (depends on 2) The device according to claim 2, wherein the rib structure comprises a length extending in a first direction along the rib structure and a width extending in a direction that is substantially perpendicular to the length, and wherein a fin structure in the first rib channel comprises a width that extends substantially in a same direction as the width of the rib structure, wherein a fin structure in the second rib channel corresponds to the fin structure in the first rib channel and comprises a width that extends substantially in a same direction as the width of the rib structure; the fin structure in the first rib channel and the corresponding fin structure in the second rib channel together comprising an optical loss that is less than or equal to about −1.4 dB for a rib structure width that is less than or equal to about 1.80 μm and a fin structure width that is less than or equal to about 2.0 μm. ### Claim 4 (depends on 3) The device according to claim 3, wherein the fin structure in the first rib channel and the corresponding fin structure in the second rib channel together comprise an optical loss that is less than or equal to about −0.7 dB for a rib structure width that is less than or equal to about 1.80 μm and a fin structure width that is less than or equal to about 1.0 μm. ### Claim 5 (depends on 4) The device according to claim 4, wherein the fin structure in the first rib channel and the corresponding fin structure in the second rib channel together comprise an optical loss that is less than or equal to about −0.2 dB for a rib structure width that is less than or equal to about 1.80 μm and a fin structure width that is less than or equal to about 0.4 μm. ### Claim 6 (depends on 2) The device according to claim 2, wherein the fin structure in the first rib channel and the corresponding fin structure in the second rib channel together comprise an optical loss that is less than or equal to about −1.4 dB for a wavelength between about 1.3 μm and about 1.6 μm. ### Claim 7 (depends on 6) The device according to claim 6, wherein the fin structure in the first rib channel and the corresponding fin structure in the second rib channel together comprise an optical loss that is less than or equal to about 0.35 db for a wavelength between about 1.3 μm and about 1.6 μm. ### Claim 8 (depends on 1) The device according to claim 1, wherein the rib structure and the rib channels are formed in a silicon-on-insulator substrate. ### Claim 9 (depends on 8) The device according to claim 8, further comprising a die bonded to the silicon-on-insulator substrate to form a hybrid silicon-optical device. ### Claim 10 (depends on 9) The device according to claim 9, wherein the die is a III-V die. ### Claim 11 A hybrid optical device, comprising: a silicon-on-insulator substrate comprising at least one waveguide, the waveguide comprising a rib structure between a first waveguide channel and a second waveguide channel, the first waveguide channel comprising a first sidewall and a second sidewall, the first sidewall of the first waveguide channel comprising a sidewall of the rib structure, and at least one fin structure formed between the first sidewall and the second sidewall of the first waveguide channel, the second waveguide channel comprising a first sidewall and a second sidewall, the first sidewall of the second waveguide channel comprising a sidewall of the rib structure, and at least one fin structure formed between the first sidewall and the second sidewall of the second waveguide channel; and a III-V die bonded to the silicon-on-insulator substrate, the III-IV die comprising circuitry coupled to at least one waveguide. ### Claim 12 (depends on 11) The device according to claim 11, wherein the rib structure comprises a length extending in a first direction along the rib structure and a width extending in a direction that is substantially perpendicular to the length, and wherein at least one fin structure in the first rib channel comprises a width that extends substantially in a same direction as the width of the rib structure, wherein a fin structure in the second rib channel corresponds to the fin structure in the first rib channel and comprises a width that extends substantially in a same direction as the width of the rib structure; the fin structure in the first rib channel and the corresponding fin structure in the second rib channel together comprising an optical loss that is less than or equal to about −1.4 dB for a rib structure width that is less than or equal to about 1.80 μm and a fin structure width that is less than or equal to about 2.0 μm. ### Claim 13 (depends on 12) The device according to claim 12, wherein the fin structure in the first rib channel and the corresponding fin structure in the second rib channel together comprise an optical loss that is less than or equal to about −0.7 dB for a rib structure width that is less than or equal to about 1.80 μm and a fin structure width that is less than or equal to about 1.0 μm. ### Claim 14 (depends on 13) The device according to claim 13, wherein the fin structure in the first rib channel and the corresponding fin structure in the second rib channel together comprise an optical loss that is less than or equal to about −0.2 dB for a rib structure width that is less than or equal to about 1.80 μm and a fin structure width that is less than or equal to about 0.4 μm. ### Claim 15 (depends on 11) The device according to claim 11, wherein the fin structure in the first rib channel and the corresponding fin structure in the second rib channel together comprise an optical loss that is less than or equal to about −1.4 dB for a wavelength between about 1.3 μm and about 1.6 μm. ### Claim 16 (depends on 15) The device according to claim 15, wherein the fin structure in the first rib channel and the corresponding fin structure in the second rib channel together comprise an optical loss that is less than or equal to about 0.35 db for a wavelength between about 1.3 μm and about 1.6 μm.