Chip structure and preparation method thereof

A Micro-LED vertical chip structure, comprising:

• an epitaxial structure, the epitaxial structure comprising a first doping type semiconductor layer, a second doping type semiconductor layer, and an active layer disposed between the first doping type semiconductor layer and the second doping type semiconductor layer, wherein a mesa structure is formed by etching on a side of the second doping type semiconductor layer facing away from the active layer and is located in the middle of the second doping type semiconductor layer, wherein the epitaxial structure further comprises a confinement layer, the confinement layer is formed on the periphery of the mesa structure by epitaxial growth and is in contact with the mesa structure, and the confinement layer has a second doping type, a first doping type, or no doping type;
• and
• a second electrode electrically connected to the second doping type semiconductor layer, wherein the second electrode is formed on a surface of the mesa structure;
• wherein the Micro-LED vertical chip structure further comprises an insulation layer formed at least on a surface of the confinement laver facing away from the active layer and extending from the surface along a side surface of the confinement layer to a side surface of the active layer, and the second electrode is electrically isolated from the confinement laver via the insulation layer,
• wherein a material of the confinement layer is a semiconductor material composed of any one of Group III elements Ga, In, and Al, and any one of Group V elements N, As, and P, wherein a space charge region is formed between the confinement layer and the second doping type semiconductor layer, and the space charge region controls a current flow path to allow current to bypass the side surface of the mesa structure, and
• wherein in a case that the confinement layer has the second doping type, a doping concentration of the confinement layer is less than a doping concentration of the second doping type semiconductor layer in contact with the confinement layer, and in a case that the confinement layer contains Al, the Al content is less than 0.5%.