Epitaxial growth method for improving reverse electric leakage of GaN-based light-emitting diode (LED)

Abstract

The invention provides an epitaxial growth method for improving reverse electric leakage of a GaN-based light-emitting diode (LED). An epitaxial structure for inhibiting linear dislocation comprises a 50-200nm non-doped u-Al GaN epitaxial layer inserted at the 4 / 5 thickness of a high-temperature u-GaN layer, 4-8 periodic n-Al GaN / GaN superlattice layers inserted at the 1 / 3 thickness of the high-temperature u-GaN layer, and a 2-6nm low-doped n-Al GaN layer growing behind a low-doped n-GaN layer; (2) an epitaxial structure for inhibiting V-type detect electric leakage comprises a 10-50nm non-doped Al GaN layer growing behind the last base of a multi-quantum well (MQW), and a 50-200nm low-doped p-Al GaN layer inserted between a low-temperature p-GaN layer and a high-temperature p-GaN layer. After the epitaxial growth method is adopted, the linear dislocation and the V-type detect density in a GaN epitaxial layer can be effectively reduced, electric leakage channels in a chip can be reduced, and the reverse electric leakage of the chip is effectively improved; the average value Ir of the electric leakage test of the 9*9mil chip produced by the epitaxy technique is equal to 0.0038mu A @-8V.

Description

technical field [0001] The invention relates to the technical field of preparation of gallium nitride-based LEDs, in particular to an epitaxial growth method for improving reverse leakage of GaN-based LEDs. Background technique [0002] Semiconductor light-emitting diodes (light-emission diodes, LEDs) have been well used in indicator lights, display screens, backlights and other fields due to their advantages of small size, low energy consumption, long life, environmental protection and durability. At present, blue and green LEDs mainly use GaN as the base material. Due to the lack of GaN substrates, the current GaN epitaxial layer mainly uses sapphire (Al 2 o 3 ) as the epitaxial substrate material. However, due to the large lattice mismatch (>11%) and large thermal expansion coefficient difference between GaN and sapphire substrate, there is a high density (~10 8 -10 10 cm -2 ) lattice defects such as dislocations. Transmission electron microscopy (TEM), scanning ...

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Problems solved by technology

These a large number of threading dislocations and V-type defects have become the main leakage channels of LED chips. Holes and electrons will form non-radiative coincidences through threading dislocation lines and V-type defects, reducing the internal quantum efficiency of the device and deteriorating the device. performance

Research [Y.Chen, atl, Applied Physics Letters72,710] shows that the epitaxial AlGaN layer on GaN can significantly suppress the linear defect and V-type defect density in the GaN epitaxial layer, but generally the AlGaN layer insertion will increase the forward direction of the device. Voltage

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