White LED and manufacturing method therefor

• US 7,737,460 B2
• Filed: 02/09/2006
• Issued: 06/15/2010
• Est. Priority Date: 02/10/2005
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Asakawa, Koji, Fujimoto, Akira
• Primary Examiner(s): Nguyen; Kimberly D
• Assistant Examiner(s): Belousov; Alexander
• Application Number:
  US11/349,986
• Publication Number:
  US 20060186424A1
• Time in Patent Office: 1,587 Days
• Field of Search: 257 79-103, 257/E33.027, 257/E33.058, 257/E25.005
• US Class Current: 257/99
• CPC Class Codes: H01L 2933/0083 Periodic patterns for optical field-shaping in or on the semiconductor body or semiconductor body package, e.g. photonic bandgap structures
• CPC Class Codes: H01L 2933/0091 Scattering means in or on the semiconductor body or semiconductor body package H01L33/22 takes precedence
• CPC Class Codes: H01L 33/44 characterised by the coatings, e.g. passivation layer or anti-reflective coating

Abstract

A white LED includes an LED chip formed on one main surface of a sapphire substrate, the LED chip being formed in a semiconductor stack structure including a light emitting layer and emitting light of a predetermined wavelength, a light extracting film applied on the other main surface of the substrate, the light extracting film being formed of a material having a refractive index within a range of ±5% of a refractive index of the substrate and a surface of the light extracting film that is located on an opposite side to the substrate being processed into a recess and projection shape, and a phosphor member provided on an opposite side of the substrate with respect to the light extracting film, and generating white light as light is incident thereon.

Claims

1. A white light emitting diode (LED) comprising:

a crystalline sapphire substrate having a first main surface and a second main surface located on an opposite side to the first main surface;

a light emitting diode (LED) chip formed on the first main surface of the substrate, the LED chip being fabricated in a semiconductor stack structure including a light emitting layer and emitting light of a predetermined wavelength;

a light extracting film formed on the second main surface of the substrate, the light extracting film being formed of a material having a refractive index within a range of ±

5% of a refractive index of the substrate, and having a surface located on an opposite side to the substrate and processed into a recess and projection shape by having recesses extending into a portion of the light extracting film; and

a phosphor member provided on the light extracting film on an opposite side thereof to the substrate, the phosphor member generating white light due to light incident thereon through the light extracting film,

wherein the light extracting film is formed of an SiON film, a Y₂O₃ film, a MgO film, a Sm₂O₃ film, a Nd₂O₃ film, an amorphous Al₂O₃ film, or an SiO₂-TiO₂ film,

wherein an interval between adjacent projections of the recess and projection shape of the light extracting film is 50 nm to 1 μ

m and a height of each of the projections is 100 nm to 1 μ

m.

2. The white LED according to claim 1, wherein the LED chip emits UV light and the phosphor member converts UV light into white light.