Hydrogen mitigation schemes in the passivation of advanced devices
View Patent ↗Embodiments of a Silicon Nitride (SiN) passivation structure for a semiconductor device are disclosed. In general, a semiconductor device includes a semiconductor body and a SiN passivation structure over a surface of the semiconductor body. In one embodiment, the SiN passivation structure includes one or more Hydrogen-free SiN layers on, and preferably directly on, the surface of the semiconductor body, a Hydrogen barrier layer on, and preferably directly on, a surface of the one or more Hydrogen-free SiN layers opposite the semiconductor body, and a Chemical Vapor Deposition (CVD) SiN layer on, and preferably directly on, a surface of the Hydrogen barrier layer opposite the one or more Hydrogen-free SiN layers. The Hydrogen barrier layer preferably includes one or more oxide layers of the same or different compositions. Further, in one embodiment, the Hydrogen barrier layer is formed by Atomic Layer Deposition (ALD).
1. A semiconductor device comprising:
a semiconductor body; and
a passivation structure on a surface of the semiconductor body, the passivation structure comprising:
one or more Hydrogen-free Silicon Nitride layers on the surface of the semiconductor body;
a Hydrogen barrier layer having more than one oxide layer on a surface of the one or more Hydrogen-free Silicon Nitride layers opposite the semiconductor body; and
an additional Silicon Nitride layer on a surface of the Hydrogen barrier layer opposite the one or more Hydrogen-free Silicon Nitride layers.
2. The semiconductor device of claim 1 wherein the one or more oxide layers are formed via Atomic Layer Deposition.
3. The semiconductor device of claim 1 wherein at least two of the one or more oxide layers have different compositions.
4. The semiconductor device of claim 1 wherein the additional Silicon Nitride layer contains a substantial amount of Hydrogen.
5. The semiconductor device of claim 4 wherein the additional Silicon Nitride layer is a Plasma Enhanced Chemical Vapor Deposition Silicon Nitride layer.
6. The semiconductor device of claim 4 wherein the one or more Hydrogen-free Silicon Nitride layers are one or more sputtered Silicon Nitride layers.
7. The semiconductor device of claim 1 wherein the semiconductor device is a Metal Semiconductor Field Effect Transistor.
8. The semiconductor device of claim 1 wherein the semiconductor device is a High Electron Mobility Transistor.
9. The semiconductor device of claim 1 further comprising:
a source region in the semiconductor body;
a drain region in the semiconductor body;
a source contact on the surface of the semiconductor body adjacent to the source region;
a drain contact on the surface of the semiconductor body adjacent to the drain region; and
a gate contact on the surface of the semiconductor body between the source region and the drain region;
wherein the passivation structure is on the surface of the semiconductor body at least between the source contact and the gate contact and between the drain contact and the gate contact.
10. The semiconductor device of claim 1 wherein the semiconductor device is a Metal Oxide Semiconductor Field Effect Transistor.
11. The semiconductor device of claim 10 further comprising:
a source region in the semiconductor body;
a drain region in the semiconductor body;
a source contact on the surface of the semiconductor body adjacent to the source region;
a drain contact on the surface of the semiconductor body adjacent to the drain region;
an insulator layer on the surface of the semiconductor body between the source contact and the drain contact; and
a gate contact on a surface of the insulator layer between the source contact and the drain contact opposite the semiconductor body;
wherein the passivation structure is on the surface of the insulator layer opposite the semiconductor body at least between the source contact and the gate contact and between the drain contact and the gate contact.
12. The semiconductor device of claim 10 further comprising:
a source region in the semiconductor body;
a drain region in the semiconductor body;
a source contact on the surface of the semiconductor body adjacent to the source region; and
a drain contact on the surface of the semiconductor body adjacent to the drain region;
wherein the passivation structure comprises:
a first Hydrogen-free Silicon Nitride layer on the surface of the semiconductor body between the source region and the drain region and having an opening for a gate contact;
an insulator layer on a surface of the first Hydrogen-free Silicon Nitride layer opposite the semiconductor body and on the surface of the semiconductor body within the opening for the gate contact;
one or more second Hydrogen-free Silicon Nitride layers on a surface of the insulator layer opposite the first Hydrogen-free Silicon Nitride layer and the semiconductor body;
the Hydrogen barrier layer on a surface of the one or more second Hydrogen-free Silicon Nitride layers opposite the insulator layer; and
the additional Silicon Nitride layer on the surface of the Hydrogen barrier layer opposite the one or more second Hydrogen-free Silicon Nitride layers;
further wherein the semiconductor device further comprises the gate contact on the surface of the insulator layer between the insulator layer and the one or more second Hydrogen-free Silicon Nitride layers and over the opening for the gate contact.
13. A semiconductor device comprising:
a semiconductor body; and
a passivation structure on a surface of the semiconductor body, the passivation structure comprising:
one or more sputtered Silicon Nitride layers on the surface of the semiconductor body;
a Hydrogen barrier layer having more than one oxide layer on a surface of the one or more sputtered Silicon Nitride layers opposite the semiconductor body; and
an additional layer of Silicon Nitride on a surface of the Hydrogen barrier layer opposite the one or more sputtered Silicon Nitride layers.
14. A method of fabricating a passivation structure for a semiconductor device comprising:
providing one or more Hydrogen-free Silicon Nitride layers on a surface of a semiconductor body of the semiconductor device;
providing a Hydrogen barrier layer having more than one oxide layer on a surface of the one or more Hydrogen-free Silicon Nitride layers opposite the semiconductor body; and
providing an additional Silicon Nitride layer on a surface of the Hydrogen barrier layer opposite the one or more Hydrogen-free Silicon Nitride layers.
15. The method of claim 14 wherein providing the one or more oxide layers comprises depositing the one or more oxide layers by Atomic Layer Deposition.
16. The method of claim 14 wherein providing the one or more oxide layers comprises providing at least two oxide layers having different compositions.
17. The method of claim 14 wherein providing the additional Silicon Nitride layer comprises providing the additional Silicon Nitride layer such that the additional Silicon Nitride layer contains a substantial amount of Hydrogen.
18. The method of claim 17 wherein providing the additional Silicon Nitride layer comprises depositing the additional Silicon Nitride layer by Plasma Enhanced Chemical Vapor Deposition.
19. The method of claim 17 wherein the providing the one or more Hydrogen-free Silicon Nitride layers comprises sputtering the one or more Hydrogen-free Silicon Nitride layers.
20. The method of claim 17 wherein the semiconductor device is a Metal Semiconductor Field Effect Transistor.
21. The method of claim 14 wherein the semiconductor device is a High Electron Mobility Transistor.
22. The method of claim 14 wherein the semiconductor device is a Metal-Oxide-Semiconductor Field Effect Transistor.
23. A method of fabricating a passivation structure for a semiconductor device comprising:
providing one or more sputtered Silicon Nitride layers on a surface of a semiconductor body of the semiconductor device;
providing a Hydrogen barrier layer having more than one oxide layer on a surface of the one or more sputtered Silicon Nitride layers opposite the semiconductor body; and
providing an additional Silicon Nitride layer on a surface of the Hydrogen barrier layer opposite the one or more sputtered Silicon Nitride layers.