GaN light-emitting diodes with low-temperature p-type GaN layer

Abstract

The invention relates to GaN light-emitting diodes with a low-temperature p-type GaN layer. The main difference between the structure of the GaN light-emitting diodes of the invention and the structure of the existing GaN light-emitting diodes is that a low-temperature p-type GaN layer grows between an InGaN/GaN multiple-quantum well active light-emitting layer and a p-type AlGaN electron blocking layer, thereby physically separating the InGaN/GaN multiple-quantum well active light-emitting layer from the p-type AlGaN electron blocking layer on an interface. Results show that the luminous intensity and reverse breakdown voltage of the GaN light-emitting diodes are greatly improved.

Description

technical field [0001] The invention relates to a gallium nitride (GaN) light-emitting diode, in particular to a gallium nitride light-emitting diode with a low-temperature p-type GaN layer. Background technique [0002] At present, III-V semiconductor optoelectronic materials are known as the third generation semiconductor materials. GaN-based light-emitting diodes have become the focus of industry research because they can produce light-emitting diodes (referred to as "LEDs") of various colors (especially blue or violet light that requires a high energy gap) by controlling the composition of materials. [0003] The epitaxial growth of GaN-based semiconductor materials or devices currently mainly adopts MOCVD technology. In the process of growing nitride semiconductors (GaN, AlN, InN and their alloy nitrides) using MOCVD technology, sapphire is usually used as the substrate for heteroepitaxy because there is no substrate material that matches the GaN lattice. However, the...

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Problems solved by technology

On the one hand, the compressive stress caused by lattice mismatch will form a large compressive strain electric field (ie, piezoelectric field effect) effect)), and the existence of the piezoelectric field effect will make the wave functions of electrons and holes separated in space, thus causing the weakening of the radiative recombination intensity

In addition, the mechanical stress caused by the above-mentioned compressive strain will further deteriorate the quality of the epitaxial layer, thereby affecting the luminous intensity of the device

Secondly, the p-type AlGaN electron blocking layer must be grown above 1000°C to obtain better crystal quality, while the growth temperature of the InGaN / GaN MQW active layer is 700°C to 850°C, so when InGaN / GaN MQW When the temperature rises above 1000°C after the growth of the active layer, the structure of the InGaN / GaN multi-quantum well active layer grown at low temperature will be destroyed, thus affecting the luminous efficiency of the light-emitting diode

Thirdly, since the growth temperature of the p-type AlGaN electron blocking layer is relatively high, and the diffusion coefficient of the p-type dopant (such as Mg) increases rapidly at high temperature, during the high-temperature growth of the p-type AlGaN electron blocking layer, the p Type dopants will inevitably diffuse into the underlying InGaN / GaN multi-quantum well active region, which will have a serious impact on light-emitting diodes

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