US 5159700 A
A circuit composed of a circuit board of crystalline elemental silicon slice and circuit components in the form of semiconductor integrated circuits therein which are preferably formed of a Group III-V compound. Signals from each of the integrated circuits
US 5159700 A
A circuit composed of a circuit board of crystalline elemental silicon slice and circuit components in the form of semiconductor integrated circuits therein which are preferably formed of a Group III-V compound. Signals from each of the integrated circuits are transmitted to other integrated circuits on the board or externally of the board either by conventional printed conductors on the board or by a laser formed in each integrated circuit at each output terminal thereon which transmits light signals along light transmitting members in the silicon board to detectors at the input locations on other ones of the integrated circuits on the board for external to the board. The light signal is transferred from an integrated circuit output to an integrated circuit input or to a device external to the board by means of light transmitting members. These light transmitting members may be light conducting waveguides positioned either on the surface of the board or in grooves formed therein. Alternatively, the light transmitting members can be silicon dioxide paths formed in the silicon circuit board by selective oxidation of the silicon board to form silicon dioxide light transmitting paths therein. Each light transmitting path is coupled between a light emitting output from an integrated circuit and a light receiving input of another integrated circuit on the same or a different semiconductor chip or travels to the edge of the circuit board for transmission external of the board.
1. A method of forming an optical communication system which comprises the steps of:
(a) providing a silicon substrate;
(b) forming a channel in said silicon substrate capable of transmitting light frequency signals;
(c) forming a group III-V semiconductor light transmitting device on said silicon substrate optically coupled to said channel; and
(d) forming a group III-V semiconductor light receiving device on said silicon substrate optically coupled to said channel.
2. The method of claim 1 wherein said step of forming said channel comprises the steps of etching grooves in said silicon substrate and filling said etched grooves with silicon oxide.
3. The method of claim 2 wherein said silicon oxide is SiO.sub.2 doped with germanium.
4. The method of claim 1 wherein said step of forming said channel comprises the steps of masking said silicon substrate to expose predetermined regions of said silicon substrate and oxidizing the exposed predetermined regions of said silicon substrate to form silicon oxide in said exposed regions.
5. The method of claim 1 wherein said Group III-V composition is gallium arsenide.
6. The method of claim 2 wherein said Group III-V composition is gallium arsenide.
7. The method of claim 3 wherein said Group III-V composition is gallium arsenide.
8. The method of claim 4 wherein said Group III-V composition is gallium arsenide.
9. An optical communication system which comprises:
(a) a silicon substrate;
(b) a channel in said silicon substrate capable of transmitting light frequency signals;
(c) a group III-V semiconductor light transmitting device on said substrate optically coupled to said channel; and
(d) a group III-V semiconductor light receiving device on said silicon substrate optically coupled to said channel.
10. The system of claim 9 wherein said channel comprises grooves in said silicon substrate filled with silicon oxide.
11. The system of claim 10 wherein said silicon oxide is SiO.sub.2 doped with germanium.
12. The system of claim 9 wherein said Group III-V composition is gallium arsenide.
13. The system of claim 10 wherein said Group III-V composition is gallium arsenide.
14. The system of claim 11 wherein said Group III-V composition is gallium arsenide.
Referring now to FIGS. 1 and 2, there is shown a circuit board 1 formed of a silicon slice and having positioned thereon a plurality of semiconductor chips 3 preferably formed from a Group III-V material, which are secured to the top surface of the board 1 by appropriate bonding techniques. A plurality of guided optic channels 5 are formed in or on the board in manner to be described in more detail hereinbelow. Coupling elements 7 couple outputs 9 (FIG. 3) from the chip 3 to guided optic channels 5 and also couple the guided optic channels 5 to inputs 11 (FIG. 3) to the chips 3. Each of the chips 3 has either or both of a light emitting output element 9 which can be in the form of a laser diode which is coupled to one of the quided optic channels 5 as shown in FIG. 3 and an input element 11, preferably in the form of a photo responsive diode which is also coupled to a guided optic channel 5. The guided optic channels 5 as shown in FIG. 3 also provide communication between plural circuit boards or a circuit board and an external optical transmitter and/or receiver.
The guided optic channel 5 can be formed in several ways. In accordance with the first embodiment, grooves are formed in the upper surface of the circuit board I and standard guided optic elements 5 are deposited and secured therein. When such standard guided optic elements are utilized, the material from which the circuit board is formed need not be silicon but can be any standard board material. As a second alternative, the circuit board 1 will be of crystalline silicon and the quided optic channels 5 are formed therein by standard semiconductor oxidation techniques wherein, for example, a silicon nitride pattern will be formed on the surface of the board 1 and the board will then either be etched in the regions where the guided optic channels are to be formed with subsequent oxidation of the exposed silicon to fill the channel with silicon dioxide or, alternatively, after pattern formation with silicon nitride, the exposed silicon wil