Method for fabricating a semiconductor structure including a metal oxide interface with silicon

• US 6,709,989 B2
• Filed: 06/21/2001
• Issued: 03/23/2004
• Est. Priority Date: 06/21/2001
• Status: Expired due to Fees

• Current Assignee: Apple Inc.
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Ramdani, Jamal, Yu, Zhiyi, Droopad, Ravindranath
• Primary Examiner(s): Niebling, John F.
• Assistant Examiner(s): Simkovic, Viktor
• Application Number:
  US09/885,409
• Publication Number:
  US 20020197881A1
• Time in Patent Office: 1,006 Days
• Field of Search: 438/216, 438/483, 438/680, 438/683, 438/764, 438/3, 438/479, 438/480-481, 438/606-607, 438/763, 117/101, 117/105, 117/108
• US Class Current: 438/763
• CPC Class Codes: H01L 21/02172 the material containing at least one metal element, e.g. metal oxides, metal nitrides, metal oxynitrides or metal carbides materials containing silicon H01L21/02123; metal silicates H01L21/02142
• CPC Class Codes: H01L 21/0228 deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD
• CPC Class Codes: H01L 21/02304 formation of intermediate layers, e.g. buffer layers, layers to improve adhesion, lattice match or diffusion barriers
• CPC Class Codes: H01L 21/3141 Deposition using atomic layer deposition techniques [ALD]
• CPC Class Codes: H01L 21/316 composed of oxides or glassy oxides or oxide based glass
• CPC Class Codes: H01L 21/31604 Deposition from a gas or vapour H01L21/31691, H01L21/31695 take precedence
• CPC Class Codes: H01L 21/31616 Deposition of Al2O3
• CPC Class Codes: H01L 21/31645 Deposition of Hafnium oxides, e.g. HfO2
• CPC Class Codes: H01L 21/31691 with perovskite structure

Abstract

A method of fabricating a semiconductor structure including the steps of:

providing a silicon substrate having a surface;

forming by atomic layer deposition a monocrystalline seed layer on the surface of the silicon substrate; and

forming by atomic layer deposition one or more layers of a monocrystalline high dielectric constant oxide on the seed layer,

where providing a substrate includes providing a substrate having formed thereon a silicon oxide, and wherein forming by atomic layer deposition a seed layer further includes depositing a layer of a metal oxide onto a surface of the silicon oxide, flushing the layer of metal oxide with an inert gas, and reacting the metal oxide and the silicon oxide to form a monocrystalline silicate.

Claims

1. A method of fabricating a semiconductor structure comprising:

providing a silicon substrate having a surface;

forming by atomic layer deposition a monocrystalline seed layer on the surface of the silicon substrate, the seed layer formed of a silicate material; and

forming by atomic layer deposition one or more layers of a monocrystalline high dielectric constant oxide on the seed layer,

wherein forming by atomic layer deposition the seed layer of a silicate material includes forming the seed layer of a silicate material selected from the group of strontium silicon oxide (SrSiO₄), zirconium silicon oxide (ZrSiO₄), and hafnium silicon oxide (HfSiO₄),

wherein forming by atomic layer deposition one or more layers of a monocrystalline high dielectric constant oxide on the seed layer includes forming the layer of high dielectric constant oxide selected from the group of hafnium oxide (HfO₂), zirconium oxide (ZrO₂), strontium titanate (SrTiO₃), lanthanum oxide (La₂O₃), yttrium oxide (Y₂O₃), titanium oxide (TiO₂), barium titanate (BaTiO₃), lanthanum aluminate (LaAlO₃), lanthanum scandium oxide (LaScO₃) and aluminum oxide (Al₂O₃),

wherein providing a substrate includes providing a substrate having formed thereon a silicon oxide, and

wherein forming by atomic layer deposition a monocrystalline seed layer further includes depositing a layer of a metal oxide onto a surface of the silicon oxide, flushing the layer of metal oxide with an inert gas, reacting the metal oxide with the silicon oxide to form the silicate selected from the group of strontium silicon oxide (SrSiO₄), zirconium silicon oxide (ZrSiO₄), and hafnium silicon oxide (HfSiO₄).

2. A method of fabricating a semiconductor structure comprising:

providing a silicon substrate having a surface;

forming by atomic layer deposition a monocrystalline seed layer on the surface of the silicon substrate, the seed layer formed of a silicate material; and

forming by atomic layer deposition one or more layers of a monocrystalline high dielectric constant oxide on the seed layer,

wherein forming by atomic layer deposition the seed layer of a silicate material includes forming the seed layer of a silicate material selected from the group of strontium silicon oxide (SrSiO₄), zirconium silicon oxide (ZrSiO₄), and hafnium silicon oxide (HfSiO₄),

wherein forming by atomic layer deposition one or more layers of a monocrystalline high dielectric constant oxide on the seed layer includes forming the layer of high dielectric constant oxide selected from the group of hafnium oxide (HfO₂), zirconium oxide (ZrO₂), strontium titanate (SrTiO₃), lanthanum oxide (La₂O₃), yttrium oxide (Y₂O₃), titanium oxide (TiO₂), barium titanate (BaTiO₃), lanthanum aluminate (LaAlO₃), lanthanum scandium oxide (LaScO₃) and aluminum oxide (Al₂O₃),

wherein providing a substrate includes providing a substrate having a layer of hydrogen formed thereon by hydrogen passivation.

3. A method of fabricating a semiconductor structure as claimed in claim 2 wherein forming by atomic layer deposition a seed layer further includes desorbing the layer of hydrogen formed on the substrate, exposing the silicon substrate to a silicon precursor and at least one metal precursor forming a layer of a silicon and a metal on the surface of the silicon substrate, flushing the layer of silicon with an inert gas to remove any excess silicon and metal precursor material, exposing the surface of the layer of silicon to at least one of oxygen (O₂) with or without plasma, water (H₂O), nitrous oxide (N₂O), or nitric oxide (NO) to oxidize the layer of silicon and metal thereby forming a single oxidized monolayer, and flushing the oxidized monolayer with an inert gas.

4. A method of fabricating a semiconductor structure as claimed in claim 3 further including repeating the atomic layer deposition to form oxidized monolayers.

5. A method of fabricating a semiconductor structure comprising:

providing a silicon substrate having a surface;

forming by atomic layer deposition a monocrystalline seed layer on the surface of the silicon substrate, the seed layer formed of a silicate material; and

forming by atomic layer deposition one or more layers of a monocrystalline high dielectric constant oxide on the seed layer,

wherein forming by atomic layer deposition the seed layer of a silicate material includes forming the seed layer of a silicate material selected from the group of strontium silicon oxide (SrSiO₄), zirconium silicon oxide (ZrSiO₄), and hafnium silicon oxide (HfSiO₄),

wherein forming by atomic layer deposition one or more layers of a monocrystalline high dielectric constant oxide on the seed layer includes forming the layer of high dielectric constant oxide selected from the group of hafnium oxide (HfO₂), zirconium oxide (ZrO₂), strontium titanate (SrTiO₃), lanthanum oxide (La₂O₃), yttrium oxide (Y₂O₃), titanium oxide (TiO₂), barium titanate (BaTiO₃), lanthanum aluminate (LaAlO₃), lanthanum scandium oxide (LaScO₃) and aluminum oxide (Al₂O₃),

whereby the forming by atomic layer deposition one or more layers of a monocrystalline high dielectric constant oxide includes exposing the monocrystalline seed layer to a metal precursor, thereby forming a layer of metal, flushing the layer of metal with an inert gas, exposing the layer of metal to at least one of oxygen (O) with or without plasma, water (H₂O), nitrous oxide (N₂O), or nitric oxide (NO) to oxidize the layer of metal thereby forming a single monocrystalline high-k oxidized monolayer, and flushing the oxidized monolayer with an inert gas.

6. A method of fabricating a semiconductor structure as claimed in claim 5 further including repeating the atomic layer deposition to form monocrystalline high-k oxide of a desired thickness.