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Making Smooth Surfaces on Polycrystalline Silicon

IP.com Disclosure Number: IPCOM000086370D
Original Publication Date: 1976-Aug-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Brodsky, MH: AUTHOR [+2]

Abstract

In field-effect transistor (FET) technology, when metallurgy is placed above the polysilicon gate, short circuits sometimes occur through the oxide insulating layer in the crossover regions. Such short circuits are often the result of a rough surface in the polysilicon. Electrical breakdowns in this region are avoided by smoothing the polycrystalline silicon surfaces before oxidation.

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Making Smooth Surfaces on Polycrystalline Silicon

In field-effect transistor (FET) technology, when metallurgy is placed above the polysilicon gate, short circuits sometimes occur through the oxide insulating layer in the crossover regions. Such short circuits are often the result of a rough surface in the polysilicon. Electrical breakdowns in this region are avoided by smoothing the polycrystalline silicon surfaces before oxidation.

A SiO(2) insulating layer is deposited on the polysilicon by a glow discharge decomposition of vapors containing silicon and oxygen, in an environment that gives a smooth polysilicon - SiO(2) interface.

Many gases are capable of being used, for example mixtures of silane and carbon dioxide, or mixtures containing tetraethoxysilane.

However, to achieve the smooth poly-si surface, the early stages of the glow discharge deposition should contain gases which give silicon alone rather than silicon dioxide, for example, silane without carbon dioxide. Thus a smoothing deposition of silicon leading gradually to silicon dioxide is formed.

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