A suitable vacuum is established inside the plasma source 1 and the diffusion chamber 2, and nitrogen in the form of gaseous nitrogen N2 or ammonia NH3 is introduced at the upstream end via the gas inlet 7, silicon is brought into the diffusion chamber in post-discharge via the post-discharge gas inlet 8 in the form of silane SiH4, and the plasma is generated by powering the RF generator 6. The plasma propagates into the diffusion chamber 2 as far as the substrate carried by the substrate support 3. A deposited layer of silicon nitride Si3N4 is thus formed on the substrate.
To perform a plasma-enhanced chemical vapor deposition method, a substrate is placed on the substrate support 3 which is fitted into position 3a in the diffusion chamber.
The diffusion chamber 2 also includes a post-discharge gas inlet 8 enabling gas to be introduced downstream from the plasma-creation zone, whereas the gas inlet 7 serves to introduce gas upstream from the plasma-creation zone.
The plasma source 1 communicates with the diffusion chamber 2 which is itself adapted to direct the plasma towards a substrate held on the substrate support in position 3a.
The plasma source 1 is constituted by an enclosure whose wall 4 is made of dielectric material, it is advantageously cylindrical in shape, being associated with a loop antenna 5 powered by a radiofrequency (RF) electrical generator 6. A gas inlet 7 is provided at the proximal end of the plasma source 1, i.e. at its end remote from the diffusion chamber 2.
Reference is made initially to FIG. 1. Apparatus for plasma-enhanced chemical vapor deposition of a dielectric film comprises a plasma source 1, preferably a high-density ion source in order to be capable of operating properly at a lower operating temperature, followed by a diffusion chamber 2 having a substrate support 3 adapted to hold the substrate for treatment and to be engaged in the diffusion chamber 2, as shown in position 3a.
After which, the ALD chamber is purged prior to introducing the precursor used to deposit the remainder of the dielectric material. FIG. 5 shows the substrate 10 following formation of the interfacial layer 20.


After introducing the metal nitrate comprising precursor, the chamber is purged with nitrogen, or an inert gas as shown in step 114. In one embodiment the precursor will be pulsed alternately with the purge, as indicated by process arrow 116. The alternating process can continue as desired, for example until the interfacial layer has reached saturation, and the process becomes self-limited.
It is preferable for these gases to be eliminated to within the limits of the ALD chamber being used.
Step 112 introduces a metal nitrate comprising precursor of the form M(NO3)x, where M is a metal and x is the valence of M, into the ALD chamber to form the interfacial layer.
Step 110 provides with a hydrogen-passivated surface within an ALD chamber. FIG. 4 shows a substrate 10 with a hydrogen-passivated surface 12. For purpose of this illustration, a field oxide 16 is shown, which might correspond to a replacement gate process.