Method of making ZnSe based light emitting device with in layer using vibration and pressure

• US 6,465,273 B1
• Filed: 05/04/2000
• Issued: 10/15/2002
• Est. Priority Date: 05/13/1999
• Status: Expired due to Fees

• Current Assignee: Sumitomo Electric Industries Limited (Sumitomo Corporation)
• Original Assignee: Sumitomo Electric Industries Limited (Sumitomo Corporation)
• Inventors: Matsubara, Hideki, Katayama, Koji, Saegusa, Akihiko
• Primary Examiner(s): Pham, Long
• Assistant Examiner(s): TOLEDO, FERNANDO L
• Application Number:
  US09/564,194
• Time in Patent Office: 894 Days
• Field of Search: 438/84, 438/102, 438/603, 438/120, 438/118, 438/612, 438/615, 257/626, 362/800
• US Class Current: 438/84
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 33/28 containing only elements of Group II and Group VI of the Periodic Table
• CPC Class Codes: H01L 33/40 Materials therefor

Abstract

A light emitting device includes an LED chip fixed to an electrode body via a conductive layer of In or an In alloy. The conductive layer is in ohmic-contact with an n-type ZnSe crystal substrate of the LED chip. To make the device, In or an In alloy is melted on the electrode body, the ZnSe substrate is placed directly on the melted In or In alloy and then subjected to at least one of vibration and pressure to achieve a good bond and ohmic contact between the In or In alloy and the ZnSe substrate.

Claims

1. A method of manufacturing a light emitting device, comprising the steps of:

providing a light emitting layer and an electrode on an n-type ZnSe substrate having a carrier concentration of at least 3×

10¹⁷ cm<sup>−

3</sup> and less than 3×

10¹⁸ cm<sup>−

3</sup>;

melting In or an In alloy into a melted state on an electrode base;

placing said n-type ZnSe substrate directly on said In or In alloy in said melted state and applying at least one of vibration and pressure to said substrate; and

performing a thermal treatment after the step of applying at least one of said vibration and said pressure.

2. The method of claim 1, wherein said vibration is ultrasonic vibration.

3. The method of claim 1, wherein said pressure is at least 0.544 MPa and less than 109 MPa.

4. The method of claim 1, wherein:

said vibration includes a scrubbing operation provided by a mechanical vibration of at least 1 Hz and at most 1000 Hz in frequency;

said pressure is at least 0.217 MPa and less than 109 MPa; and

said vibration and said pressure are applied simultaneously.

5. The method of claim 4, wherein:

said frequency is at least 10 Hz and at most 300 Hz; and

said pressure is at least 0.217 MPa and at most 10.9 MPa.

6. The method of claim 4, wherein:

said frequency is at least 10 Hz and at most 60 Hz; and

said pressure is at least 0.217 MPa and at most 5.45 MPa.

7. The method of claim 1, wherein said thermal treatment is performed at a temperature of 250°

C.

8. The method of claim 1, wherein said steps together result in said light emitting device having an operating voltage between said electrode and said electrode base of not more than 3 volts with an injected current of 20 mA.

9. A method of assembling a light emitting device comprising the steps:

a) providing a light emitting diode including an n-type ZnSe substrate having a carrier concentration of at least 3×

10¹⁷ cm<sup>−

3</sup> and less than 3×

10¹⁸ cm<sup>−

3</sup>, and a light emitting layer on said substrate;

b) melting an In-based material containing at least 50% of In into a melted state at a first temperature on an electrode member;

c) placing said substrate of said light emitting diode directly into contact with said In-based material in said melted state on said electrode member, and applying at least one of vibration and pressure between said substrate and said electrode member relative to each other; and

d) after said step c), heat treating said substrate and said In-based material at a heat treating temperature greater than said first temperature.

10. The method according to claim 9, wherein said In-based material is In.

11. The method according to claim 9, wherein said heat treating temperature is in a range from 200°

C. to 250°

C.

12. The method according to claim 9, wherein said step c) comprises applying both said vibration and said pressure simultaneously.

13. The method according to claim 9, wherein said step c) comprises applying only said vibration without said pressure.

14. The method according to claim 9, wherein said step c) comprises applying only said pressure without said vibration, and said pressure is at least 0.544 MPa and less than 109 MPA.