Silicon heterojunction photovoltaic device with wide band gap emitter

• US 9,373,743 B2
• Filed: 03/19/2015
• Issued: 06/21/2016
• Est. Priority Date: 11/07/2011
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Hekmatshoar-Tabari, Bahman, Khakifirooz, Ali, Sadana, Devendra K., Shahidi, Ghavam G., Shahrjerdi, Davood
• Primary Examiner(s): Mandala, Victor A
• Assistant Examiner(s): Rundio, Regan J
• Application Number:
  US14/662,597
• Publication Number:
  US 20150194562A1
• Time in Patent Office: 460 Days
• US Class Current: 1/1
• CPC Class Codes: H01L 21/02381 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/0243 Surface structure
• CPC Class Codes: H01L 21/02433 Crystal orientation
• CPC Class Codes: H01L 21/02458 Nitrides
• CPC Class Codes: H01L 21/02461 Phosphides
• CPC Class Codes: H01L 21/02463 Arsenides
• CPC Class Codes: H01L 21/02466 Antimonides
• CPC Class Codes: H01L 21/0254 Nitrides
• CPC Class Codes: H01L 21/02543 Phosphides
• CPC Class Codes: H01L 21/02546 Arsenides
• CPC Class Codes: H01L 21/02549 Antimonides
• CPC Class Codes: H01L 21/02576 N-type
• CPC Class Codes: H01L 21/02579 P-type
• CPC Class Codes: H01L 21/0262 Reduction or decomposition of gaseous compounds, e.g. CVD
• CPC Class Codes: H01L 21/26513 of electrically active species
• CPC Class Codes: H01L 31/02167 for solar cells
• CPC Class Codes: H01L 31/022425 for solar cells
• CPC Class Codes: H01L 31/022441 Electrode arrangements specially adapted for back-contact solar cells
• CPC Class Codes: H01L 31/022466 made of transparent conductive layers, e.g. TCO, ITO layers
• CPC Class Codes: H01L 31/02363 of the semiconductor body itself, e.g. textured active layers
• CPC Class Codes: H01L 31/02366 : of the substrate or of a layer on the substrate, e.g. textured ITO/glass substrate or superstrate, textured polymer layer on glass substrate
• CPC Class Codes: H01L 31/03044 : comprising a nitride compounds, e.g. GaN
• CPC Class Codes: H01L 31/03048 : comprising a nitride compounds, e.g. InGaN
• CPC Class Codes: H01L 31/0336 : in different semiconductor regions, e.g. Cu2X/CdX hetero- junctions, X being an element of Group VI of the Periodic Table
• CPC Class Codes: H01L 31/036 : characterised by their crystalline structure or particular orientation of the crystalline planes
• CPC Class Codes: H01L 31/0682 : back-junction, i.e. rearside emitter, solar cells, e.g. interdigitated base-emitter regions back-junction cells
• CPC Class Codes: H01L 31/072 : the potential barriers being only of the PN heterojunction type
• CPC Class Codes: H01L 31/074 : comprising a heterojunction with an element of Group IV of the Periodic Table, e.g. ITO/Si, GaAs/Si or CdTe/Si solar cells
• CPC Class Codes: H01L 31/18 : Processes or apparatus specially adapted for the manufacture or treatment of these devices or of parts thereof
• CPC Class Codes: H01L 31/1852 : comprising a growth substrate not being an AIIIBV compound
• CPC Class Codes: H01L 31/1868 : Passivation
• CPC Class Codes: H01L 31/1884 : Manufacture of transparent electrodes, e.g. TCO, ITO
• CPC Class Codes: Y02E 10/544 : Solar cells from Group III-V materials
• CPC Class Codes: Y02E 10/547 : Monocrystalline silicon PV cells

Abstract

A photovoltaic device including a single junction solar cell provided by an absorption layer of a type IV semiconductor material having a first conductivity, and an emitter layer of a type III-V semiconductor material having a second conductivity, wherein the type III-V semiconductor material has a thickness that is no greater than 50 nm.

Claims

1. A method of forming a photovoltaic device comprising:

providing an absorption layer of a crystalline type IV semiconductor material having a first conductivity type;

epitaxially depositing a buffer layer of a type III-V semiconductor material on the absorption layer, wherein the buffer layer of the type III-V semiconductor material is an intrinsic semiconductor material; and

epitaxially forming an emitter layer of a crystalline type III-V semiconductor material having a second conductivity type on a surface of the buffer layer.

2. The method of claim 1, wherein the absorption layer is provided by a silicon-containing substrate.

3. The method of claim 2, wherein a surface of the silicon-containing substrate is textured to provide a (111) crystal surface.

4. The method of claim 3, wherein the surface of the silicon-containing substrate is textured by treating the surface of the silicon-containing substrate with a wet etch comprised of at least one of potassium hydroxide (KOH), potassium carbonate (K₂CO₃), nitric acid (HNO₃), hydrofluoric acid (HF) or a combination thereof, or the surface of the silicon-containing substrate is textured with reactive ion etch (RIE).

5. The method of claim 1, wherein the epitaxially forming the emitter layer of the crystalline type III-V semiconductor material having the second conductivity comprises deposition of the crystalline type III-V semiconductor material in direct contact with the buffer layer.

6. The method of claim 5, wherein the epitaxial growth of the crystalline type III-V semiconductor material is performed using a solid sources containing In, Ga, N, P elements and combinations thereof, and/or a gas precursor selected from the group consisting of trimethylgallium (TMG), trimethylindium (TMI), tertiary-butylphosphine (TBP), phosphine (PH₃), ammonia (NH₃), and combinations thereof.

7. The method of claim 1, wherein the second conductivity of the emitter layer is an opposite conductivity as compared with the first conductivity of the absorption layer.

8. The method of claim 7, wherein a second dopant that provides the second conductivity of the emitter layer is introduced to the crystalline type III-V semiconductor material in-situ during epitaxial growth of the crystalline type III-V semiconductor material that provides the emitter layer.

9. The method of claim 8, wherein the second dopant is provided by a dopant gas selected from the group consisting of bis-cyclopentadienyl-magnesium (Cp₂Mg), silane (SiH₄), disilane (Si₂H₆), germane (GeH₄), carbon tetrabromide (CBr₄) and combinations thereof.

10. The method of claim 1, wherein the emitter layer has a thickness that is 50 nm or less.

11. The method of claim 1, wherein the crystalline type III-V semiconductor material has a defect density that ranges from 10¹³ defects/cm³ to 10¹⁹ defects/cm³.

12. The method of claim 1, wherein the first conductivity type is p-type and the second conductivity type is n-type.

13. The method of claim 1, wherein the first conductivity type is n-type and the second conductivity type is p-type.