Nitride semiconductor structure
View Patent ↗A nitride semiconductor structure of the present disclosure comprises a semiconductor substrate, and a layer formed over the semiconductor substrate and comprising plural nitride semiconductor layers. The semiconductor substrate has, from a side thereof near the layer comprising the plural nitride semiconductor layers, a surface region and an internal region in this order. The surface region has a resistivity of 0.1 Ωcm or more, and the internal region has a resistivity of 1000 Ωcm or more.
1. A nitride semiconductor structure comprising:
a semiconductor substrate, and
a layer formed over the semiconductor substrate and comprising plural nitride semiconductor layers,
wherein the semiconductor substrate has, from a side thereof near the layer comprising the plural nitride semiconductor layers, a surface region and an internal region in this order,
the surface region has a resistivity of 0.1 Ωcm or more, and the internal region has a resistivity of 1000 Ωcm or more, and
a central portion of the semiconductor substrate has an oxygen concentration higher than that of an end portion of the semiconductor substrate.
2. The nitride semiconductor structure according to claim 1 , wherein the semiconductor substrate has an oxygen concentration ranging from 1×10 17 cm −3 to 5×10 18 cm −3 both inclusive.
3. A nitride semiconductor structure comprising:
a semiconductor substrate, and
a layer formed over the semiconductor substrate and comprising plural nitride semiconductor layers,
wherein the semiconductor substrate has, from a side thereof near the layer comprising the plural nitride semiconductor layers, a surface region and an internal region in this order,
the surface region has a resistivity of 0.1 Ωcm or more, and the internal region has a resistivity of 1000 Ωcm or more, and
the semiconductor substrate has an oxygen concentration distribution, and a thickness of the layer comprising the plural nitride semiconductor layers above a high-oxygen concentration region of the semiconductor substrate is larger than a thickness of the layer comprising the plural nitride semiconductor layers above a low-oxygen concentration region of the semiconductor substrate.
4. A nitride semiconductor structure comprising:
a semiconductor substrate, and
a layer formed over the semiconductor substrate and comprising plural nitride semiconductor layers,
wherein the semiconductor substrate has, from a side thereof near the layer comprising the plural nitride semiconductor layers, a surface region and an internal region in this order,
the surface region has a resistivity of 0.1 Ωcm or more, and the internal region has a resistivity of 1000 Ωcm or more, and
the surface region has a lower oxygen concentration than the internal region.
5. The nitride semiconductor structure according to claim 1 , wherein the layer comprising the plural nitride semiconductor layers has a thickness of 1000 nm or more.
6. The nitride semiconductor structure according to claim 1 , wherein a source electrode, a drain electrode, and a gate electrode are formed on the layer comprising the plural nitride semiconductor layers.
7. The nitride semiconductor structure according to claim 6 , wherein a semiconductor layer containing a p-type impurity is formed between the gate electrode and the layer comprising the plural nitride semiconductor layers.
8. The nitride semiconductor structure according to claim 6 , wherein the semiconductor substrate is electrically connected to the source electrode or the drain electrode.
9. The nitride semiconductor structure according to claim 1 , wherein a positive electrode and a negative electrode are formed on the layer comprising the plural nitride semiconductor layers.
10. The nitride semiconductor structure according to claim 9 , wherein the semiconductor substrate is electrically connected to the positive electrode or the negative electrode.
11. The nitride semiconductor structure according to claim 1 , wherein the layer comprising the plural nitride semiconductor layers comprises a buffer layer, a channel layer formed over the buffer layer, and a barrier layer formed over the channel layer and having a larger bandgap energy than the channel layer.
12. The nitride semiconductor structure according to claim 11 , wherein the buffer layer comprises carbon.
13. The nitride semiconductor structure according to claim 12 , wherein the carbon comprised in the buffer layer has a concentration ranging from 1×10 18 cm −3 to 1×10 20 cm −3 both inclusive.
14. The nitride semiconductor structure according to claim 11 , wherein the channel layer comprises carbon.
15. The nitride semiconductor structure according to claim 14 , wherein the carbon comprised in the channel layer has a concentration of 1×10 18 cm −3 or less.