SOI substrate and method for manufacturing the same
AssigneeNEC Corporation
InventorAtsushi Ogura
Life of this patent
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Abstract
A SOI substrate includes a SiO2 film (230) having a center located at the depth of the damage peak where the crystal damage is maximum after the Si substrate (10) is ion-implanted with oxygen ions. Even if a crystal defect (240) remains at the depth of the density peak where the density is maximum, the crystal defect does not effect the device operation because it is outside the active layer. By using a low-dose SIMOX process, a lower-cost SOI substrate can be obtained wherein crystal defects formed in the active layer are reduced.
Claims13
A SOI substrate comprising at SiO2 film formed in a silicon substrate and extending substantially parallel to a main surface of said silicon substrate, and a plurality of SiO2 islands substantially all disposed below said SiO2 film and arranged in a direction substantially parallel to said main surface.
A SOI substrate comprising a SiO2 film formed in a silicon substrate and extending substantially parallel to a main surface of said silicon substrate, a plurality of SiO2 islands disposed below said SiO2 film and arranged in a direction substantially parallel to said main surface, and a crystal defect bridging said SiO2 film and one of said SiO2 islands.
A SOI substrate comprising a first buried SiO2 film formed in a silicon substrate and extending substantially parallel to a main surface of said silicon substrate, a second buried SiO2 film extending below said first buried SiO2 film substantially parallel to said main surface, and a crystal defect bridging said first buried SiO2 film and said second buried SiO2 film.
A method for manufacturing a SOI substrate comprising a SiO2 film formed in a silicon substrate and extending substantially parallel to a main surface of said silicon substrate, and a plurality of SiO2 islands disposed said SiO2 film and arranged in a direction substantially parallel to said main surface, comprising the steps of:
- implanting oxygen ions in a silicon substrate, raising an ambient temperature of the silicon substrate wherein the temperature is raised at a rate not higher than 1°/minute over a range of at least 100° above a temperature higher than 600 □ while an ambient oxygen concentration is kept at a level of 0.5% or higher, and heat treating the silicon substrate at a temperature not lower than 1200° for a specified time length.
The method for manufacturing a SOI substrate comprising the steps of:
- implanting oxygen ions in a silicon substrate to form a damage peak where crystal defects generated by the ion implantation is maximum and a density peak where a concentration of the implanted oxygen ions is maximum in the silicon substrate;
- and
- forming an SiO2 film extending in a direction parallel to a main surface of the silicon substrate and having a center located substantially at the damage peak.
Dependencies are inferred from the claim text.