Method for selectively depositing a layer on a three dimensional structure
A method may include providing a substrate having a surface that defines a substrate plane and a substrate feature that extends from the substrate plane; directing an ion beam comprising angled ions to the substrate at a non-zero angle with respect to a perpendicular to the substrate plane, wherein a first portion of the substrate feature is exposed to the ion beam and wherein a second portion of the substrate feature is not exposed to the ion beam; directing molecules of a molecular species to the substrate wherein the molecules of the molecular species cover the substrate feature; and providing a second species to react with the molecular species, wherein selective growth of a layer comprising the molecular species and the second species takes place such that a first thickness of the layer grown on the first portion is different from a second thickness grown on the second portion.
1. A method of selectively doping a three dimensional substrate feature on a substrate, comprising:
exposing the substrate to an oxide plasma wherein the substrate feature is covered with a sub-monolayer of oxygen;
directing an ion beam comprising angled ions to the substrate at a non-zero angle with respect to a perpendicular to a substrate plane when the substrate feature is covered with the sub-monolayer of oxygen, wherein a first portion of the substrate feature is exposed to the ion beam and wherein a second portion of the substrate feature is not exposed to the ion beam, wherein the sub-monolayer of oxygen is removed in the first portion and the sub-monolayer of oxygen remains in the second portion; and
after the directing the ion beam, directing molecules of a molecular species that includes a dopant to the substrate wherein the molecules of the molecular species cover the substrate feature,
wherein the directing the ion beam and directing the molecules generates selective growth of a dopant oxide layer comprising the dopant on the second portion but not on the first portion.
2. The method of claim 1 further comprising;
depositing a sealing layer on the substrate; and
annealing the substrate wherein a doped region is formed in the three dimensional substrate feature adjacent the second portion.
3. The method of claim 1 , wherein the angled ions comprise hydrogen ions that are effective to react with oxygen to remove the oxygen in the exposed regions.
4. The method of claim 1 , wherein the angled ions are inert gas ions having an ion energy and ion dose that is effective to remove the sub-monolayer of oxygen.
5. The method of claim 1 ,
wherein the dopant oxide layer is a monolayer,
wherein exposing the substrate to an oxide plasma, directing an ion beam comprising angled ions, and the directing molecules of a molecular species comprise a process cycle that is effective to selectively deposit a monolayer and,
wherein the process cycle is repeated and wherein a plurality of monolayers are formed.
6. The method of claim 1 , further comprising modifying a plasma sheath boundary to generate the angled ions.
7. The method of claim 1 , wherein the angled ions comprise an ion angular distribution that has a bimodal distribution of angles of incidence.
8. The method of claim 1 , wherein the bimodal distribution is characterized by a peak at +/−5 degrees with respect to the perpendicular.