Patent EP0434233A1 successfully refreshed from Google Patents.
← Back to Patent Explorer
EP0434233A1 Expired / Lapsed EP ⏱️ 0.0 years remaining

Light-emitting diode with an electrically conductive window layer

Assignee: HP Inc
•
Filing: 1990-11-23
•
Granted: —
•
Expires: 2010-11-23
📄 Original PDF 🌐 Google Patents 🔄 Sync Now

Abstract

Abstract A light-emitting diode has a semiconductor substrate (35) underlying active p-N junction layers of AlGaInP (32,33,34) for emitting light. A transparent window layer (36) of semiconductor different from AlGaInP overlies the active layers and has a lower electrical resistivity than the active layers and a bandgap greater than the bandgap of the active layers, for minimizing current crowding from a metal electrical contact over the transparent window layer. The active layers may be epitaxially grown on a temporary GaAs substrate (31). A layer of lattice mismatched GaP (35) is then grown on the active layers with the GaP having a bandgap greater than the bandgap of the active layers so that it is transparent to light emitted by the LED. The GaAs temporary substrate (31) is then selectively etched away so that the GaP acts as a transparent substrate. A transparent window layer (36) may be epitaxially grown over the active layers on the face previously adjacent to the GaAs substrate.

Inventors

  • 👤 Robert M. Fletcher
  • 👤 Chihping Kuo
  • 👤 Timothy Osentowski
  • 👤 Virginia M. Robbins

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-04 15:20
CPC Classifications
H; H10; H10H; H10H20/00; H10H20/80; H10H20/81; H10H20/822; H10H20/824; H10H20/01; H10H20/011; H10H20/013

Claims Analysis

Total Claims: 9
Claim 1
Independent Claim 68 words
A light emitting diode comprising: a semiconductor substrate (20); an electrical contact (26) to the substrate; active p-n junction layers of AlGaInP (21,22,23) over the substrate for emitting light; a transparent window layer (24) of semiconductor different from AlGaInP over the active layers and having a bandgap greater than the bandgap of the active layers; and a metal electrical contact (25) over a portion of the transparent layer.
Claim 2
Dependent Claim 87 words
A light emitting diode according to claim 1 wherein said active p-n junction layers comprise; a first confining layer of n-type AlGaInP (21) on the substrate; an active layer of n-type AlGaInP (22) on the first confining layer; and a second confining layer of p-type AlGaInP (23) on the active layer; and wherein the transparent window layer of semiconductor different from AlGaInP, over the second confining layer, has a lower resistivity than the second confining layer and a bandgap greater than the bandgap of the active layer.
Claim 3
Dependent Claim 87 words
A light emitting diode according to claim 1 wherein said active p-n junction layers comprise: a first confining layer of p-type AlGaInP (21) on the substrate; an active layer of p-type AlGaInP (22) on the first confining layer; and a second confining layer of n-type AlGaInP (23) on the active layer; and wherein the transparent window layer of semiconductor different from AlGaInP, over the second confining layer, has a lower resistivity than the second confining layer and a bandgap greater than the bandgap of the active layer.
Claim 4
Dependent Claim 22 words
A light emitting diode according to any of claims 1 to 3 wherein the transparent window layer comprises AlGaAs, GaAsP, or GaP.
Claim 5
Dependent Claim 33 words
A light emitting diode according to any of claims 1 to 4 wherein the transparent window layer has a resistivity at least an order of magnitude less than the resistivity of the AlGaInP.
Claim 6
Dependent Claim 17 words
A light emitting diode according to any of claims 1 to 5 wherein the substrate is opaque.
Claim 7
Dependent Claim 17 words
A light emitting diode according to any of claims 1 to 6 wherein the substrate comprises GaAs.
Claim 8
Dependent Claim 19 words
A light emitting diode according to claim 1 or 2 wherein the transparent window layer comprises a p-type semiconductor.
Claim 9
Dependent Claim 17 words
A light emitting diode according to claim 3 wherein the transparent window layer comprises an n-type semiconductor.

References Cited (Backward Citations)

US4775876A Cited
EP0334637A2 Cited
EP0342656A2 Cited
US4864369A Cited

USPTO Annuity & Maintenance Windows

Maintenance schedule is calculated for granted US utility patents.

Assigned Categories & Tags

No categories assigned to this patent yet.

Assign Category Tag