EPITAXIAL SUBSTRATE AND METHOD FOR FORMING THE SAME
First Claim
1. An epitaxial substrate, comprising:
- a substrate;
a deposition layer formed on the substrate directly, wherein the deposition layer includes a gradient doping concentration, and has a first surface and a second surface which are opposite to each other;
the gradient doping concentration has a minimum value at the first surface;
a buffer layer formed on the deposition layer; and
an epitaxial layer formed on the buffer layer, and the epitaxial layer is mainly formed of group III-V nitride;
wherein, the substrate and the deposition layer are formed of homogeneous material;
the deposition layer includes a gradient resistivity which includes a high impedance layer region which has a resistivity at least greater than 1500 ohm-cm.
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Abstract
An epitaxial substrate and a method for forming the same are disclosed. The epitaxial substrate includes a substrate, a deposition layer, a buffer layer and an epitaxial layer. The deposition layer is directly formed on the substrate, wherein the deposition layer includes a gradient doping concentration, and has a first surface and a second surface which are opposite to each other; the gradient doping concentration has a minimum value at the first surface. The buffer layer is formed on the deposition layer, and an epitaxial layer is formed on the buffer layer. The epitaxial layer is mainly formed of group III-V nitride. The substrate and the deposition layer are formed of homogeneous material. Since the deposition layer is directly formed on the substrate, and the deposition layer and the substrate are formed of a homogeneous material, the epitaxial substrate includes a good heat dissipation efficiency and low leakage current.
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Citations
23 Claims
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1. An epitaxial substrate, comprising:
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a substrate; a deposition layer formed on the substrate directly, wherein the deposition layer includes a gradient doping concentration, and has a first surface and a second surface which are opposite to each other;
the gradient doping concentration has a minimum value at the first surface;a buffer layer formed on the deposition layer; and an epitaxial layer formed on the buffer layer, and the epitaxial layer is mainly formed of group III-V nitride;
wherein, the substrate and the deposition layer are formed of homogeneous material;
the deposition layer includes a gradient resistivity which includes a high impedance layer region which has a resistivity at least greater than 1500 ohm-cm. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method for forming an epitaxial substrate, comprising:
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A. providing a substrate; B. forming a deposition layer on the substrate, wherein the deposition layer and the substrate are formed of homogeneous material;
the deposition layer includes a gradient doping concentration and has a first surface and a second surface which are opposite to each other;
the gradient doping concentration has a minimum value at the first surface;
the deposition layer includes a gradient resistivity which includes a high impedance layer region having a resistivity at least greater than 1500 ohm-cm;C. forming a buffer layer on the deposition layer; and D. forming an epitaxial layer on the buffer layer, wherein the epitaxial layer is mainly formed of group III-V nitride. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23)
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Specification