Method of producing a semiconductor body with a trench, semiconductor body with at least one trench and semiconductor device
A method is proposed of producing a semiconductor body with a trench. The semiconductor body comprises a substrate. The method comprising the step of etching the trench into the substrate using an etching mask. An oxide layer is formed at least on a sidewall of the trench by oxidation of the substrate. A passivation layer is formed on the oxide layer and the bottom of the trench. The passivation layer is removed from the bottom of the trench. Finally, a metallization layer is deposited into the trench.
1. A method of producing a semiconductor body with a trench, wherein the semiconductor body comprises a substrate, the method comprising:
etching the trench into the substrate using an etching mask,
forming an oxide layer at least on a sidewall of the trench by oxidation of the substrate,
forming a passivation layer on the oxide layer and a bottom of the trench,
removing the passivation layer from the bottom of the trench, and
depositing a metallization layer into the trench;
wherein the steps of etching the trench, forming the oxide layer, and forming and removing the passivation layer are repeated until the trench has a desired depth.
2. The method according to claim 1 , wherein the oxidation of the substrate involves:
a wet-chemical oxidation process, and/or
an oxidation induced by an atmospheric plasma.
3. The method according to claim 2 , wherein the wet-chemical procedure involves an oxidizing agent which is applied into the trench via the etching mask.
4. The method according to claim 2 , wherein the atmospheric plasma comprises an oxidizing species as process gas.
5. The method according to claim 2 , wherein the atmospheric plasma comprises ozone and/or oxygen.
6. The method according to claim 1 , wherein the oxidation is performed at a temperature below the melting point of the substrate and/or other materials used for the semiconductor.
7. The method according to claim 1 , wherein
the oxidation is performed at a temperature below 800° C., and/or
the oxidation is performed at a temperature from a range of 150° C. to 400° C.
8. The method according to claim 1 , wherein
the substrate comprises bulk silicon, and
the oxide layer comprises SiO 2 , which is formed by the oxidation of bulk silicon.
9. The method according to claim 8 , wherein the oxidation of bulk silicon is performed in an oxygen plasma such that a film SiO 2 is grown on the sidewall at temperatures down to room temperature.
10. The method according to claim 9 , wherein the oxygen plasma comprises a Helium and Oxygen mixture.
11. The method according to claim 1 , wherein
further etching the trench into the substrate involves using the etching mask and the remaining passivation layer on the sidewall.
12. The method according to claim 1 , wherein the metallization is electrically connected to electrodes such that the trench is operable as a through-substrate via.
13. The method according to claim 1 , wherein the steps of etching the trench, forming the oxide layer, and forming and removing the passivation layer are performed in sequence.