In this exemplary embodiment, the first insulating layer 108 is made of silicon oxide or silicon nitride.

An ohmic contact layer 105 is further formed between the second semiconductor layer 103 and the second contact electrode 107 for reducing the contact resistance between the second contact electrode 107 and the second semiconductor layer 103. In this exemplary embodiment, the ohmic contact layer 105 is made of indium tin oxide.

The LED chip further includes: a first extension electrode 111 located on the first contact electrode 106 and electrically connected to the first contact electrode 106, and including a plurality of concave spots for soldering; and a second extension electrode 121 located on the second contact electrode 107, electrically connected to the second contact electrode 107, isolated from the first extension electrode 111, and including a plurality of concave spots 130 for soldering.

As shown in FIG. 12, in this exemplary embodiment, each of the first extension electrode 111 and the second extension electrode 121 is a circular extension electrode, and an entire area of the circular extension electrode is used to form the plurality of concave spots 130. In the subsequent soldering process, the solder is likely to form a circular extension surface. The circular extension electrode with a plurality of concave points 130 in the LED chip of the exemplary embodiment matches the shape of the circular extension surface. A larger soldering area can be obtained by a smaller extension electrode area, thereby improving the utilization ratio of the first extension electrode 111 and the second extension electrode 121.