Method of forming semiconductor structure
AssigneeHitachi Europe Limited
InventorJeremy Allam
Life of this patent
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Abstract
Semiconductor structures and a method of forming semiconductor structures The avalanche breakdown characteristics, such as breakdown voltage and impact ionisation coefficient, of a semiconductor structure can be controlled by controlling the Brilluin-zone-averaged energy bandgap (<Ec>) of the material forming the structure. Consequently, the avalanche breakdown characteristics of a device may be tailored independently of the bandgap Eg. The Brillouin-zone-averaged energy bandgap (<Ec>) may be controlled by controlling the composition of the semiconductor used or by straining its lattice.
Claims48
A method of fabricating a semiconductor structure device with a predetermined architecture and functionality, comprising:
- determining a relationship between the Brillouin-zone-averaged energy bandgap <Ec> and the breakdown characteristic pertinent to devices with said architecture and functionality;
- selecting a breakdown characteristic;
- determining a value of Brillouin-zone-averaged energy bandgap (<Ec>) for the structure corresponding to the selected breakdown characteristic, by using said relationship;
- selecting from predetermined data relating to different material compositions and configurations and their corresponding values of <Ec>, a material corresponding to said selected value of <Ec>;
- and
- fabricating said device using said selected material.
A method of fabricating a semiconductor structure device with a predetermined architecture and functionality, comprising:
- selecting a predetermined breakdown characteristic for a functional part of the structure;
- determining a value of Brillouin-zone-averaged energy bandgap (<Ec>) for the structure corresponding to selected breakdown characteristic according to the formula:
- ⟨ E c ⟩ = ( V b + m ) n
- where
- Vb is the predetermined breakdown voltage, and m and n are constants;
- selecting a material corresponding to said determined value of <Ec>;
- and
- fabricating said portion of the structure from the selected material.
A method of fabricating a semiconductor structure device with a predetermined architecture and functionality, comprising:
- selecting a breakdown characteristic;
- determining a value of Brillouin-zone-averaged energy bandgap (<Ec>) and selecting a material corresponding to said determined value of <Ec> from:
- Material <Ec> (eV) Vb (V) Si 1.85 34.3 Ge 0.97 19.7 GaP 2.58 61.4 InP 2.09 46.5 GaAs 1.77 33.6 Ga0.47In0.53As 1 .65 33.2 Al0.48In0.52As 1.96 46.5 GaAs0.88Sb0.12 1.68 26.5 Al0.06Ga0.94Sb 1.06 22.0 Al0.28Ga0.72Sb 1.30 25.2 GaAs 1.77 33.6 Al0.15Ga0.85As 1.87 38.9 Al0.3Ga0.7As 1.96 44.5 Al0.4Ga0.6As 2.03 49.0 Al0.5Ga0.5As 2.09 52.4 Al0.6Ga0.4As 2.15 56.2 Ga0.52In0.48P 2.34 61.7 (Al0.24Ga0.76)0.52In0.48P 2.43 65.3 (Al0.50Ga0.50)0.52In0.48P 2.52 69.2 (Al0.75Ga0.25)0.52In0.48P 2.61 72.3 Al0.52In0.48P 2.70 76.0
- and
- fabricating said device using said selected material.
A method of fabricating a semiconductor structure device with a predetermined architecture and functionality, comprising:
- selecting a value of Brillouin-zone-averaged energy bandgap (<Ec>);
- selecting a material corresponding to said selected value of <Ec> from:
- <Eg> <Ec> Material (eV) (eV) Si 1.17 2.09 Ge 0.74 0.97 BN 5.81 8.96 BP 2.04 3.34 BAs 1.55 2.72 AlN 4.54 6.52 GaN 3.25 4.79 AlP 2.50 3.24 AlAs 2.23 2.41 AlSb 1.68 2.09 GaP 2.39 2.58 GaAs 1.52 1.77 GaSb 0.80 0.99 InP 1.42 2.09 InAs 0.41 1.51 InSb 0.23 1.03 Al.5Ga.5As 2.09 2.01 In.53Ga.47As 0.81 1.68 ZnS 3.80 4.65 ZnSe 2.96 3.78 ZnTe 2.71 2.97 CdS 2.55 4.30 CdSe 1.90 3.56 CdTe 1.92 2.78 HgTe 0.00 1.49
- and
- fabricating said device using said selected material.
A method of fabricating a semiconductor structure device with a predetermined architecture and functionality, comprising:
- selecting a value of Brillouin-zone-averaged energy bandgap (<Ec>);
- selecting a material from:
- <Eg> <Ec> Material (eV) (eV) Si 1.17 2.09 Ge 0.74 0.97 BN 5.81 8.96 BP 2.04 3.34 BAs 1.55 2.72 AlN 4.54 6.52 GaN 3.25 4.79 AlP 2.50 3.24 AlAs 2.23 2.41 AlSb 1.68 2.09 GaP 2.39 2.58 GaAs 1.52 1.77 GaSb 0.80 0.99 InP 1.42 2.09 InAs 0.41 1.51 InSb 0.23 1.03 Al.5Ga.5As 2.09 2.01 In.53Ga.47As 0.81 1.68 ZnS 3.80 4.65 ZnSe 2.96 3.78 ZnTe 2.71 2.97 CdS 2.55 4.30 CdSe 1.90 3.56 CdTe 1.92 2.78 HgTe 0.00 1.49
- and
- fabricating said device using said selected material under strain such that the strain causes the material to have a value <Ec> equal to the selected value of <Ec>.
A method of fabricating a semiconductor structure device with a predetermined architecture and functionality, comprising determining whether a material has a high enough avalanche breakdown voltage, including determining the value of the breakdown voltage of a material Vb, comprising:
- plotting points on a graph of Vb against <Ec> using data selected from the following:
- Material <Ec> (eV) Vb (V) Si 1.85 34.3 Ge 0.97 19.7 GaP 2.58 61.4 InP 2.09 46.5 GaAs 1.77 33.6 Ga0.47In0.53As 1.65 33.2 Al0.48In0.52As 1.96 46.5 GaAs0.88Sb0.12 1.68 26.5 Al0.06Ga0.94Sb 1.06 22.0 Al0.28Ga0.72Sb 1.30 25.2 GaAs 1.77 33.6 Al0.15Ga0.85As 1.87 38.9 Al0.3Ga0.7As 1.96 44.5 Al0.4Ga0.6As 2.03 49.0 Al0.5Ga0.5As 2.09 52.4 Al0.6Ga0.4As 2.15 56.2 Ga0.52In0.48P 2.34 61.7 (Al0.24Ga0.76)0.52In0.48P 2.43 65.3 (Al0.50Ga0.50)0.52In0.48P 2.52 69.2 (Al0.75Ga0.25)0.52In0.48P 2.61 72.3 Al0.52In0.48P 2.70 76.0
- fitting a line to the points on the graph in the region about the value of <Ec> for the material with the equation ⟨ E c ⟩ = ( V b + m ) n
- determining the values of m and n from the fitted line and
- determining the value Vb using <Ec>,m and n in said equation;
- and
- in dependence upon the value of Vb fabricating said device using said material.
A method of fabricating a FET comprising a source region, a drain region, a conductive channel extending between the source and drain regions and a gate for controlling conduction in the channel, comprising:
- determining a relationship between the Brillouin-zone-averaged energy bandgap (<Ec>) and the breakdown characteristic for the channel;
- selecting a breakdown characteristic for the channel;
- determining a value of Brillouin-zone-averaged energy bandgap (<Ec>) for the channel corresponding to the selected breakdown characteristic, by using a relationship between <Ec> and the breakdown characteristic for the FET;
- selecting from predetermined data relating to different material compositions and configurations and their corresponding values of <Ec>, a material corresponding to said selected value of <Ec>;
- and
- fabricating the channel from the selected material.
A method of fabricating a bipolar transistor comprising an emitter region of extrinsic semiconductor material of a first charge type, a collector region of extrinsic semiconductor material of the first charge type and base region of semiconductor material of a second charge type disposed between the emitter and collector regions, the method comprising:
- determining a relationship between the Brillouin-zone-averaged energy bandgap (<Ec>) and the breakdown characteristics for the emitter, base and collector regions;
- selecting breakdown characteristics for the emitter, base and collector regions;
- determining a value of Brillouin-zone-averaged energy bandgap (<Ec>) for each of the emitter, base and collector regions corresponding to selected breakdown characteristics, by using a relationship between <Ec> and breakdown characteristics for the emitter, base and collector regions;
- selecting from predetermined data relating to different material compositions and configurations and their corresponding values of <Ec>, materials corresponding to said selected values of <Ec>;
- and
- fabricating the emitter, base and collector regions from the selected materials.
A method of fabricating an avalanche photodiode comprising an absorption region of a semiconductor material of a p-type disposed adjacently to a multiplication region of undoped semiconductor material, the method comprising:
- determining a relationship between the Brillouin-zone-averaged energy bandgap (<Ec>) and the breakdown characteristics for the absorption and multiplication regions;
- selecting breakdown characteristics for the absorption and multiplication regions;
- determining a value of Brillouin-zone-averaged energy bandgap (<Ec>) for each of the absorption and multiplication regions corresponding to selected breakdown characteristics, by using a relationship between <Ec> and breakdown characteristics for the absorption and multiplication regions;
- selecting from predetermined data relating to different material compositions and configurations and their corresponding values of <Ec>, materials corresponding to said selected values of <Ec>;
- and
- fabricating the absorption and multiplication regions from the selected materials.
A method of fabricating a multiple quantum well avalanche photodiode comprising a plurality of absorption regions interleaved with multiplication regions, the method comprising:
- determining a relationship between the Brillouin-zone-averaged energy bandgap (<Ec>) and the breakdown characteristics for the absorption and multiplication regions;
- selecting breakdown characteristics for the absorption and multiplication regions;
- determining a value of Brillouin-zone-averaged energy bandgap (<Ec>) for each of the absorption and multiplication regions corresponding to selected breakdown characteristics, by using a relationship between <Ec> and breakdown characteristics for the absorption and multiplication regions;
- selecting from predetermined data relating to different material compositions and configurations and their corresponding values of <Ec>, material corresponding to said selected values of <Ec>;
- and
- fabricating the absorption and multiplication regions from the selected materials.
A method of fabricating a multiple quantum well avalanche photodiode comprising a superlattice absorption region disposed adjacently to a multiplication region of undoped semiconductor material, the method comprising:
- determining a relationship between the Brillouin-zone-averaged energy bandgap (<Ec>) and the breakdown characteristics for the superlattice absorption region and multiplication region;
- selecting breakdown characteristics for the absorption and multiplication regions;
- determining a value of Brillouin-zone-averaged energy bandgap (<Ec>) for each of the absorption and multiplication regions corresponding to selected breakdown characteristics, by using a relationship between <Ec> and breakdown characteristics for the absorber and multiplication regions;
- selecting from predetermined data relating to different material compositions and configurations and their corresponding values of <Ec>, materials corresponding to said selected values of <Ec>;
- and
- fabricating the absorption and multiplication regions from the selected materials.
A method of fabricating an impact ionisation avalanche transit-time (IMPATT) diode comprising an avalanche region and a drift region, the method comprising:
- determining a relationship between the Brillouin-zone-averaged energy bandgap (<Ec>) and the breakdown characteristics for the avalanche and drift regions;
- selecting breakdown characteristics for the avalanche and drift regions;
- determining a value of Brillouin-zone-averaged energy bandgap (<Ec>) for each of the absorption and multiplication regions corresponding to selected breakdown characteristics, by using a relationship between <Ec> and breakdown characteristics for the avalanche and drift regions;
- selecting from predetermined data relating to different material compositions and configurations and their corresponding values of <Ec>, materials corresponding to said selected values of <Ec>;
- and
- fabricating the avalanche and drift regions from the selected materials.
A method of improving an operational characteristic of a semiconductor charge transfer device, comprising:
- identifying one or more regions of the device in which the charge transfer characteristic, dependent on impact ionisation or avalanche breakdown, is degraded;
- replacing each of said one or more regions with a semiconductor region in which values of Eg and <Ec> are selected so as to improve the charge characteristic.
Dependencies are inferred from the claim text.