Group III-V device with a selectively modified impurity concentration
View Patent ↗There are disclosed herein various implementations of a semiconductor structure and method. The semiconductor structure comprises a substrate, a transition body over the substrate, and a group III-V intermediate body having a bottom surface over the transition body. The semiconductor structure also includes a group III-V device layer over a top surface of the group III-V intermediate body. The group III-V intermediate body has a continuously reduced impurity concentration wherein a higher impurity concentration at the bottom surface is continuously reduced to a lower impurity concentration at the top surface.
1. A semiconductor structure comprising:
a substrate;
a transition body having a bottom surface over said substrate;
a group III-V intermediate body having a bottom surface over a top surface of said transition body;
a group III-V device layer over a top surface of said group III-V intermediate body;
wherein a transition body impurity concentration at a depth position between said bottom surface of said transition body and said top surface of said transition body is greater than said transition body impurity concentration at said bottom surface of said transition body;
wherein a selectively modified impurity concentration in said group III-V intermediate body falls within said group III-V intermediate body such that a higher impurity concentration at said bottom surface of said group III-V intermediate body is reduced to a substantially lower impurity concentration at said top surface of said group III-V intermediate body;
wherein said selectively modified impurity concentration remains substantially flat within said group III-V device layer.
2. The semiconductor structure of claim 1 , wherein said transition body impurity concentration falls between said bottom surface of said transition body and said top surface of said transition body.
3. The semiconductor structure of claim 1 , wherein an impurity producing said higher and lower impurity concentrations is a P type impurity.
4. The semiconductor structure of claim 1 , wherein said selectively modified impurity concentration comprises a selectively modified carbon concentration.
5. The semiconductor structure of claim 1 , wherein said selectively modified impurity concentration includes a plurality of impurity species.
6. The semiconductor structure of claim 1 , wherein said group III-V intermediate body comprises a compositionally graded III-Nitride body having a first III-Nitride composition at said bottom surface and a second III-Nitride composition above said bottom surface.
7. The semiconductor structure of claim 1 , wherein said group III-V device layer includes at least one of a III-Nitride field-effect transistor (FET) and a III-Nitride high electron mobility transistor (HEMT).