FORMATION OF METAL NANOSPHERES AND MICROSPHERES

• US 20130049150A1
• Filed: 09/07/2012
• Published: 02/28/2013
• Est. Priority Date: 08/30/2011
• Status: Active Grant

• Current Assignee: GlobalFoundries, Inc.
• Original Assignee: International Business Machines Corporation
• Inventors: Hong, Augustin J., Jung, Woo-Shik, Kim, Jeehwan, Nah, Jae-Woong, Sadana, Devendra K.
• Granted Patent: US 9,040,428 B2
• Time in Patent Office: Days
• US Class Current: 257/431
• CPC Class Codes: C03C 15/00 Surface treatment of glass, not in the form of fibres or filaments, by etching etching or surface-brightening compositions, in general C09K13/00
• CPC Class Codes: C03C 17/06 with metals C03C17/34, C03C17/44 take precedence
• CPC Class Codes: C03C 2218/34 Masking
• CPC Class Codes: H01L 31/022433 Particular geometry of the grid contacts
• CPC Class Codes: H01L 31/02363 of the semiconductor body itself, e.g. textured active layers
• CPC Class Codes: H01L 31/035227 the quantum structure being quantum wires, or nanorods carbon nanotubes H10K85/211
• CPC Class Codes: H01L 31/035281 Shape of the body
• CPC Class Codes: H01L 31/0376 including amorphous semiconductors H01L31/0392 takes precedence
• CPC Class Codes: H01L 31/0392 including thin films deposited on metallic or insulating substrates ; characterised by specific substrate materials or substrate features or by the presence of intermediate layers, e.g. barrier layers, on the substrate textured substrates H01L31/02366
• CPC Class Codes: H01L 31/03921 including only elements of Group IV of the Periodic Table
• CPC Class Codes: H01L 31/03923 including AIBIIICVI compound materials, e.g. CIS, CIGS
• CPC Class Codes: H01L 31/03925 including AIIBVI compound materials, e.g. CdTe, CdS
• CPC Class Codes: H01L 31/056 the light-reflecting means being of the back surface reflector [BSR] type
• CPC Class Codes: H01L 31/075 the potential barriers being only of the PIN type, e.g. amorphous silicon PIN solar cells
• CPC Class Codes: Y02E 10/52 PV systems with concentrators
• CPC Class Codes: Y02E 10/541 CuInSe2 material PV cells
• CPC Class Codes: Y02E 10/548 Amorphous silicon PV cells
• CPC Class Codes: Y02E 10/549 Organic PV cells
• CPC Class Codes: Y10S 438/945 Special, e.g. metal
• CPC Class Codes: Y10S 977/773 Nanoparticle, i.e. structure having three dimensions of 100 nm or less
• CPC Class Codes: Y10S 977/779 : Possessing nanosized particles, powders, flakes, or clusters other than simple atomic impurity doping
• CPC Class Codes: Y10T 428/12014 : having metal particles
• CPC Class Codes: Y10T 428/12069 : Plural nonparticulate metal components
• CPC Class Codes: Y10T 428/12076 : Next to each other
• CPC Class Codes: Y10T 428/24479 : including variation in thickness
• CPC Class Codes: Y10T 428/24488 : Differential nonuniformity at margin
• CPC Class Codes: Y10T 428/2982 : Particulate matter [e.g., sphere, flake, etc.]

Abstract

Hemispheres and spheres are formed and employed for a plurality of applications. Hemispheres are employed to form a substrate having an upper surface and a lower surface. The upper surface includes peaks of pillars which have a base attached to the lower surface. The peaks have a density defined at the upper surface by an array of hemispherical metal structures that act as a mask during an etch to remove substrate material down to the lower surface during formation of the pillars. The pillars are dense and uniform and include a microscale average diameter. The spheres are formed as independent metal spheres or nanoparticles for other applications.

Claims

1. A substrate, comprising:

an upper surface and a lower surface, the upper surface including peaks of pillars attached to the lower surface;

the peaks having a density defined at the upper surface by an array of hemispherical metal structures that act as a mask to etch away substrate material down to the lower surface to form the pillars;

the pillars being dense and uniform and including a microscale average diameter.

2. The substrate as recited in claim 1, wherein the microscale average diameter of the pillars is between about 1 to 2 microns.

3. The substrate as recited in claim 1, wherein a distance between a base of the pillars on the lower surface includes an average distance that is no larger than two times an average pillar diameter.

4. The substrate as recited in claim 1, wherein the substrate is included in one or more of the following:

a solar cell template, a battery terminal template, a solar cell absorption surface, a substrate for an electronic device.

5. A photovoltaic device, comprising:

a substrate having an upper surface and a lower surface, the upper surface including peaks of pillars attached to the lower surface;

the peaks having a density defined at the upper surface by an array of hemispherical metal structures that act as a mask to etch away substrate material down to the lower surface to form the pillars, the pillars being dense and uniform and including a microscale average diameter; and

a continuous photovoltaic stack conformally formed over the substrate and extending over and between the plurality of pillars to form a three-dimensional structure, the photovoltaic stack configured to transduce incident radiation into current flow.

6. The device as recited in claim 5, wherein the microscale average diameter of the pillars is between about 1 to 2 microns.

7. The device as recited in claim 6, wherein a distance between a base of the pillars on the lower surface includes an average distance that is no larger than two times an average pillar diameter.

8. A nanoparticle, comprising:

a metal sphere having a diameter of less than 1 micron formed by employing surface tension on a non-wetting surface;

the metal sphere having the diameter defined in accordance with a thickness and deposition rate of a metal film from which the metal sphere is formed.

9. The nanoparticle as recited in claim 8, wherein the metal sphere is formed concurrently with a plurality of metal spheres and a standard deviation of diameters of the metal spheres from a mean diameter is less than 15%.

10. The nanoparticle as recited in claim 8, wherein the diameter is between 20 nm and 1 micron.

11. The nanoparticle as recited in claim 8, wherein the metal sphere includes one or more of tin, indium, lead, antimony, bismuth, zinc and alloys thereof.