Photoelectrochemical undercut etching of semiconductor material
First Claim
1. A method of wet etching a layer of target semiconductor material, comprising:
- providing at least one lateral side of said layer of target semiconductor material in intimate contact with at least one barrier material to form at least one interface of barrier material and target semiconductor material;
immersing the target semiconductor material and barrier material in a solution capable of etching the target semiconductor material under photoelectrochemical conditions and not capable of etching the barrier material under said photoelectrochemical conditions; and
illuminating the semiconductor material with light having a frequency above the energy bandgap of the target semiconductor material in a manner whereby to restrict photoelectrochemical etching to said interface, said light having sufficient energy to photoelectrochemically laterally etch the target semiconductor material at said interface.
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Accused Products
Abstract
Photoelectrochemical (PEC) etching is restricted to a group III nitride semiconductor-barrier interface to laterally etch or undercut the target group III nitride. The barrier interface is provided by the transparent sapphire substrate on which the target group III nitride is epitaxially grown or by a layer of material in intimate contact with the target group III nitride material and having a bandgap sufficiently high to make it resistant to PEC etching. Due to the first orientation in which this effect was first observed, it has been named backside-Illuminated photoelectrochemical (BIPEC) etching. It refers to a preferential etching at the semiconductor-barrier layer interface. The assembly can be exposed to light from any direction to effectuate bandgap-selective PEC etching. An opaque mask can be applied to limit the lateral extent of the photoelectrochemical etching.
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Citations
15 Claims
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1. A method of wet etching a layer of target semiconductor material, comprising:
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providing at least one lateral side of said layer of target semiconductor material in intimate contact with at least one barrier material to form at least one interface of barrier material and target semiconductor material;
immersing the target semiconductor material and barrier material in a solution capable of etching the target semiconductor material under photoelectrochemical conditions and not capable of etching the barrier material under said photoelectrochemical conditions; and
illuminating the semiconductor material with light having a frequency above the energy bandgap of the target semiconductor material in a manner whereby to restrict photoelectrochemical etching to said interface, said light having sufficient energy to photoelectrochemically laterally etch the target semiconductor material at said interface. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of wet etching a layer of target group III nitride semiconductor material, comprising:
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providing at least one lateral side of said layer of target semiconductor material in intimate contact with at least one barrier material to form at least one interface of barrier material and target semiconductor material;
immersing the target semiconductor material and barrier material in a solution capable of etching the target semiconductor material under photoelectrochemical conditions and not capable of etching the barrier material under said photoelectrochemical conditions; and
illuminating the semiconductor material with light having a frequency above the energy bandgap of the target semiconductor material in a manner whereby to restrict photoelectrochemical etching to said interface, said light having sufficient energy to photoelectrochemically laterally etch the target semiconductor material at said interface. - View Dependent Claims (14, 15)
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Specification