Process of forming an electronic device including an access region
An electronic device can include a channel layer; an access region having an aluminum content substantially uniform or increasing with distance from the channel layer; and a gate dielectric layer overlying and contacting the channel layer. A process of forming an electronic device can include providing a substrate and a channel layer of a III-V semiconductor material over the substrate; forming a masking feature over the channel layer; and forming an access region over the channel layer. In an embodiment, the channel layer can include GaN, and the access region has an aluminum content that is substantially uniform or increases with distance from the channel layer. In another embodiment, the process can include removing at least a portion the masking feature and forming a gate dielectric layer over the channel layer. A dielectric film of the masking feature or the gate dielectric layer contacts the channel layer.
1. A process of forming an electronic device comprising:
providing a substrate and a channel layer over the substrate, wherein the channel layer includes a III-V semiconductor material;
forming a masking feature over the channel layer;
forming an access region over the channel layer;
removing at least a portion the masking feature after forming the access region; and
forming a gate dielectric layer over the channel layer after removing the at least a portion of the masking feature,
wherein forming the masking feature, forming the gate dielectric layer, or both includes depositing a first dielectric film, wherein the first dielectric film contacts the channel layer.
2. The process of claim 1 , wherein depositing the first dielectric film includes SiO 2 or Al 2 O 3 .
3. The process of claim 1 , wherein depositing the first dielectric film comprises depositing the first dielectric film that includes a dielectric material that has a particular phase of a plurality of phases, wherein a semiconductor material of the channel layer has a lattice constant that is closer to the particular phase as compare to any other phase within the plurality of phases.
4. The process of claim 1 , wherein depositing the first dielectric film is performed such that a density of interface states and carrier traps along an interface between the first dielectric film and the channel layer is at most 1×10 15 eV −1 cm −2 .
5. The process of claim 1 , wherein forming the gate dielectric layer comprises depositing the first dielectric film.
6. The process of claim 1 , wherein forming the masking feature comprises:
depositing a dielectric layer including the first dielectric film, an etch-stop film over the first dielectric film, and a capping film over the etch-stop film;
forming a resist mask over the dielectric layer;
etching an exposed portion of the dielectric layer, wherein the masking feature includes another portion of the dielectric layer that is covered by the resist mask; and
removing the resist mask.
7. The process of claim 6 , removing the at least a portion the masking feature after forming the access region comprises removing remaining portions of the capping film and the etch-stop film.
8. The process of claim 7 , wherein forming the gate dielectric layer comprises depositing a second dielectric film over the first dielectric film, wherein a dielectric material of the second dielectric film has a conduction band at a higher energy as compared to the conduction bands of each of a dielectric material of the first dielectric film and a semiconductor material of the channel layer, and the dielectric material of the second dielectric film has a larger bandgap energy as compared to the semiconductor material of the channel layer.