High-pressure polysilicon encapsulated localized oxidation of silicon
AssigneeMotorola, Inc.
InventorsBarbara Vasquez, Michael P. Masquelier
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Abstract
A reduction in defects and lateral encroachment is obtained by utilizing a high pressure oxidation in conjunction with an oxidizable layer conformally deposited over an oxidation mask. The use of high pressure oxidation provides for the formation of LOCOS oxide without the formation of defects. Any native oxide present on the substrate surface is removed by using a ramped temperature deposition process to form oxidizable layer and/or a high temperature anneal is performed to remove the native oxide at the substrate surface. In this embodiment, any oxide which can act as a pipe for oxygen diffusion is removed. Therefore, nominal or no lateral encroachment is exhibited.
Claims11
A method of fabricating isolation oxide, comprising the steps of:
- providing a semiconductor substrate;
- forming a buffer layer on the substrate;
- forming an oxidation resistant layer on the buffer layer;
- removing selected portions of the oxidation resistant layer and the buffer layer to expose portions of the substrate;
- controlling an amount of oxide encroachment by forming an oxide layer on the exposed portions of the substrate and controlling the thickness of the oxide layer;
- conformally forming an oxidizable layer after the step of forming an oxide layer to overlay the oxide layer and the oxidation resistant layer;
- and
- oxidizing the oxidizable layer and the exposed portions of the substrate to form the isolation oxide in the portions of the substrate covered by the oxide layer, wherein oxidation is performed at high pressure.
A method of fabricating isolation oxide, comprising the steps of:
- providing a semiconductor substrate;
- forming a buffer layer on the substrate;
- forming an oxidation resistant layer on the buffer layer;
- removing selected portions of the oxidation resistant layer and the buffer layer to expose portions of the substrate;
- removing portions of the buffer layer to form a recess under the oxidation resistant layer;
- controlling an amount of oxide encroachment by forming an oxide layer on the exposed positions of the substrate and controlling the thickness of the oxide layer;
- conformally forming an oxidizable layer after the step of forming an oxide layer to overlay the oxide layer and the oxidation resistant layer, and to substantially fill the recess in the buffer layer;
- and
- oxidizing the oxidizable layer and the exposed portions of the substrate to form the isolation oxide in the portions of the substrate covered by the oxide layer, wherein oxidation is performed at high pressure.
Dependencies are inferred from the claim text.