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Producing Stabilizing Layers by Converting Si(3)N(4) into Phosphosilicate Glass during the Manufacture of MOS Devices

IP.com Disclosure Number: IPCOM000084633D
Original Publication Date: 1975-Dec-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 34K

Publishing Venue

IBM

Related People

Dunse, F: AUTHOR [+3]

Abstract

During the manufacture of highly integrated circuits in metal-oxide semiconductor (MOS) technology, a field shield of polycrystalline silicon is often used to suppress field induced inversion leakage. Under this polycrystalline silicon layer a thin silicon nitride layer is arranged, which serves as an etch stopper and a diffusion barrier for oxygen during oxidation processes. The silicon nitride layer in the gate regions is to be removed by etching. Subsequently a phosphosilicate glass layer is formed in the regions thus bared.

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Producing Stabilizing Layers by Converting Si(3)N(4) into Phosphosilicate Glass during the Manufacture of MOS Devices

During the manufacture of highly integrated circuits in metal-oxide semiconductor (MOS) technology, a field shield of polycrystalline silicon is often used to suppress field induced inversion leakage. Under this polycrystalline silicon layer a thin silicon nitride layer is arranged, which serves as an etch stopper and a diffusion barrier for oxygen during oxidation processes. The silicon nitride layer in the gate regions is to be removed by etching. Subsequently a phosphosilicate glass layer is formed in the regions thus bared.

By the method described herein (Figs. 1 and 2) stabilizing PSG layers are produced on SiO , in that the silicon nitride layer is directly transformed into phosphosilicate glass by exposing the wafers to a mixture of POCl(3), O(2) and N(2) at elevated temperatures. The thickness and the phosphorus content of the phosphosilicate glass layer are controlled by the N(2):O(2) ratio and the POCl(3) concentration, respectively.

During exposure, a phosphosilicate glass layer is formed. This layer has a stabilizing effect with regard to the diffusion of sodium ions.

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