Method for preparing semiconductor gallium nitride (GaN) extending thin film substrate

Abstract

The invention discloses a method for preparing a quasi-suspending semiconductor gallium nitride (GaN) extending thin film substrate supported by a single crystal sapphire, belonging to the technical field of gallium nitride substrates. The method comprises the steps: a GaN extending thin film on the sapphire substrate is irradiated from the sapphire substrate by an ultraviolet laser beam; the energy density of the laser beam is adjusted to lead the laser beam irradiated on the GaN extending thin film to form array figures with different energy density; and a GaN extending thin film part with high irradiation energy density and the sapphire substrate generate non-damage peeling, and a GaN extending thin film part with low irradiation energy density is still connected with the sapphire substrate to obtain the quasi-suspending semiconductor gallium nitride extending thin film substrate. A mechanical support of the GaN extending thin film substrate is still supplied by the single crystal sapphire, the GaN extending thin film substrate has enough mechanical stability to be used in the following process as the substrate, and the quasi-suspending GaN thin film substrate has less extendingstress and low defect density.

Description

technical field [0001] The invention relates to a method for preparing a gallium nitride substrate supported by a single crystal sapphire, in particular to a method for preparing a quasi-suspension semiconductor gallium nitride epitaxial film substrate supported by a single crystal sapphire. Background technique [0002] Gallium nitride (GaN) and doped GaN are important wide-bandgap semiconductor materials, which have broad application prospects in optoelectronic devices such as blue and white light-emitting diodes (LEDs), short-wavelength laser diodes (LDs) and functional electronic devices. , it involves an inestimable huge commercial and military market. At present, countries and large companies are vigorously developing devices and applications based on GaN-based semiconductor thin films. Semiconductor gallium nitride optoelectronic devices and functional electronic devices require the use of high-quality GaN epitaxial films. In order to pursue high-quality epitaxial g...

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Problems solved by technology

If a GaN epitaxial film is irradiated with an ultraviolet laser beam after reaching a certain thickness (such as 20 microns) to decompose and peel off the substrate without damage, many documents have described it (such as APPLIED PHYSICS LETTERS 72, 599 (1998); APPLIED PHYSICS LETTERS 77,1819(2000); APPLIED PHYSICS LETTERS 84,2757(2004); APPLIED PHYSICS LETTERS, 86,52108(2005)), but there are two basic bottleneck problems in this technology: 1) in sapphire Al 2 o 3 The GaN thick film epitaxially grown on a single crystal substrate has quite high stress defects due to the lattice mismatch and the difference in thermal expansion coefficient discussed above; 2) Even if the GaN thick film reaches a certain thickness (such as 20 microns), its The mechanical stability of the bottom used in the subsequent process is still not enough

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