The reflection layer structure of flip LED chips and flip LED chips
Technical field
The invention belongs to field of photoelectric technology, the dress dress LED chip that specifically relates to a kind of reflection layer structure of flip LED chips and contain this structure.
Background technology
Flip LED chips is compared with packed LED chip, flip LED chips has heat sinking function and luminous efficiency preferably, have the advantages such as low-voltage, high brightness, high reliability, high saturation current density, aspect of performance has larger advantage, has good development prospect.
Because the luminescent layer of flip LED is positioned at the centre of P type and n type semiconductor layer; the light part that luminescent layer sends penetrates downwards; but below chip, be solder side and opaque substrate; in order effectively to utilize this part light; usually can plate one deck reflector in the bottom of chip, Al or Ag material be take as main in reflector.
Using Al or Ag material during as reflector, because the adhesive force of Al or Ag material and semiconductor layer is very poor, be difficult to it be covered on the halfbody layer when making, the complex process cost is high, even after plating, its adhesion is not strong yet; In prior art, useful alundum (Al2O3) etc. is as the transition zone before silver-plated, but alundum (Al2O3) and semiconductor junction be the non-constant of bad and heat conductivility with joint efforts, LED can produce amount of heat when luminous, affects the life-span of LED chip, therefore can't fundamentally solve the shortcoming of prior art.
Summary of the invention
In order to solve the problems of the technologies described above, the purpose of this invention is to provide a kind of reflection layer structure of flip LED chips, Al or Ag material reflector can better be attached on semiconductor, and the heat of semiconductor light emitting generation is led away fast, extend the life-span of chip.
For achieving the above object, the present invention is achieved by the following technical solutions:
The semi-conducting material that aluminium nitride AlN is formed by III A family's element al and the element N of V A family chemical combination, thermal conductivity is good, and thermal coefficient of expansion is little, it is good heat shock resistance material, also find, aluminium nitride and semi-conductive adhesion property are fine, and also very good with the adhesion property of silver or aluminium simultaneously.
Based on above-mentioned technology, the present invention is used for flip LED chips by aluminium nitride, transition zone as silver or aluminium reflector, a kind of reflection layer structure of flip LED chips is provided, the reflector that comprises the downside that is arranged at P type ohmic contact layer, also there is no a transition zone between described reflector and P type ohmic contact layer, described reflector is selected from Ag reflector or Al reflector, and transition zone is selected from the AlN transition zone.
The present invention also further provides a kind of flip LED chips, includes Sapphire Substrate; Be arranged at the n type semiconductor layer of Sapphire Substrate downside; Be arranged at the p type semiconductor layer of n type semiconductor layer downside; Be arranged at the P type ohmic contact layer of p type semiconductor layer downside; Be arranged at the reflector of the downside of P type ohmic contact layer, between described reflector and P type ohmic contact layer, also there is no the AlN transition zone, described reflector is selected from Ag reflector or Al reflector.
Above-described flip LED chips, wherein, described semiconductor layer is selected from the GaN semiconductor layer.Downside in reflector also is provided with a protective layer.
Beneficial effect of the present invention is: by transition zone is set, make Al or Ag reflector and semiconductor layer adhesive force stronger, that the upper surface in reflector can be done is more smooth, and reflecting effect is better, improves the utilization ratio of light; The thermal conductivity of transition zone is very good, the heat diffusion that can in time semiconductor be produced, the useful life of the chip of prolongation.
The accompanying drawing explanation
Fig. 1 is the structural representation of the flip LED chips of the embodiment of the present invention.
Embodiment
Below in conjunction with accompanying drawing and specific embodiment, technical scheme of the present invention is elaborated.
Shown in Fig. 1, the flip LED chips of the present embodiment includes Sapphire Substrate 1, be arranged at the N-GaN layer 2 of Sapphire Substrate downside, be arranged at luminescent layer 23, the P type ohmic contact layer 4 that is arranged at P-GaN layer downside, the argentum reflecting layer 6 that is arranged at the downside of P type ohmic contact layer, N-type ohmic contact layer 5, P type welding electrode 7 and N-type welding electrode 8 in the middle of P-GaN layer 3, N-GaN layer and the P-GaN layer of N-GaN layer downside.
Before P type ohmic contact layer downside prepares argentum reflecting layer, first plating one deck aluminium nitride on P type ohmic contact layer, as the transition zone 9 between P type ohmic contact layer and argentum reflecting layer, make the adhesion of argentum reflecting layer 6 and thermal conductivity all better.For better protection argentum reflecting layer, at the downside of argentum reflecting layer, also be provided with a protective layer 10.
Above embodiment is the preferred embodiments of the present invention; the invention is not restricted to above-described embodiment; for those of ordinary skills; the any apparent change of doing on the basis that does not deviate from the technology of the present invention principle, all belong to the protection range of design of the present invention and claims.