Semiconductor etching process
First Claim
1. A process for fabricating a device comprising n-type or semi-insulating III-V semiconductor compound comprising aluminum or indium comprising the step of photoelectrochemically etching the III-V semiconductor compound by passing current through the III-V semiconductor compound, electrolytic solution with electrical conductivity greater than 0.00001 mho/cm and anode in which the photoelectrochemical etching procedure further comprises:
- a. applying a potential to the semiconductor which is between the maximum potential of the valence band of the semiconductor in the electrolytic solution and the minimum potential of the conduction band of the semiconductor in the electrolytic solution;
b. illuminating the part of the surface of the semiconductor to be etched with radiation of sufficient energy to produce holes in the valence band;
characterized in thatc. the electrolytic solution comprises nonaqueous solvent with less than 10 weight percent water.
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Abstract
A photoelectrochemical etching process is described for n-type and semi-insulating III-V semiconductor compounds that contain aluminum or indium (AlGaAs, InGaAs) in which a non-aqueous electrolyte is used. High etch rates are achieved without harm to exposed metallization or p-layers. An exemplatory application is the separation of chips (e.g., LED chips) after wafer processing.
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Citations
17 Claims
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1. A process for fabricating a device comprising n-type or semi-insulating III-V semiconductor compound comprising aluminum or indium comprising the step of photoelectrochemically etching the III-V semiconductor compound by passing current through the III-V semiconductor compound, electrolytic solution with electrical conductivity greater than 0.00001 mho/cm and anode in which the photoelectrochemical etching procedure further comprises:
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a. applying a potential to the semiconductor which is between the maximum potential of the valence band of the semiconductor in the electrolytic solution and the minimum potential of the conduction band of the semiconductor in the electrolytic solution; b. illuminating the part of the surface of the semiconductor to be etched with radiation of sufficient energy to produce holes in the valence band; characterized in that c. the electrolytic solution comprises nonaqueous solvent with less than 10 weight percent water. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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Specification