High conductivity buried layer in optical waveguide
First Claim
1. An optical device having an active region (108;
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312;
408;
512) for radiation propagation and injecting means (110;
202, 204;
410, 414;
514, 520) for injecting charge carriers into the active region, characterised in that the injecting means incorporates a high conductivity buried layer (104;
202;
306, 308;
402;
506) between two wafer elements of a bonded wafer couplet and the device incorporates concentrating means (204;
414) between the buried layer and the active region for concentration of charge carriers in the active region.
2 Assignments
0 Petitions
Accused Products
Abstract
An optical device (300) comprises a multilayer structure, formed by wafer bonding, incorporating in sequence a silicon dioxide layer (304), a buried silicide layer (306), a contact layer (308) and a silicon surface layer (310). The surface layer (310) is selectively etched to form an exposed rib (312). An upper surface of the rib (312) is doped to form an elongate electrode (314) therealong. The surface layer (310) is selectively etched to the contact layer (308) in regions remote from the rib (312) to form via channels (316a, 316b) for making electrical connection to the contact layer (308). The rib (312) forms a waveguide along which radiation propagates. When the electrode (314) is biased relative to the contact layer (308), charge carriers are injected into the rib (312) and induce refractive index changes in a central region (324) thereof where most of the radiation propagates along the rib (312). The silicide layer (306) provides an efficient current conduction path for injecting the carriers, thereby providing enhanced device operating bandwidth and reduced power dissipation.
76 Citations
31 Claims
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1. An optical device having an active region (108;
-
312;
408;
512) for radiation propagation and injecting means (110;
202, 204;
410, 414;
514, 520) for injecting charge carriers into the active region, characterised in that the injecting means incorporates a high conductivity buried layer (104;
202;
306, 308;
402;
506) between two wafer elements of a bonded wafer couplet and the device incorporates concentrating means (204;
414) between the buried layer and the active region for concentration of charge carriers in the active region. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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312;
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25. A method of fabricating an optical device including the steps of:
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(a) providing first and second wafer elements (700, 702;
850, 856);
(b) providing the wafer elements with a layer structured (706, 708, 710;
854, 862, 858) to define injecting means for injecting charge carriers into an active device region for radiation propagation;
(c) providing one of the wafer elements with a metal silicide (708) or a polysilicon layer (862) to provide injecting means;
(d) bonding the wafer elements to form a wafer couplet (714;
866) within which the metal silicide layer or the polysilicon layer is buried; and
(e) processing the couplet (714;
866) to define the active device region.- View Dependent Claims (26, 27, 28, 29, 30, 31)
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Specification