Epitaxial wafer for use in the production of an infrared LED

摘要

The present invention relates to a wafer for use in the production of an infrared LED. Conventionally, infrared LEDs are produced by using an epitaxial wafer comprising P- and N-type GaAs epitaxial layers. The wafer according to the present invention is characterized by having a P-type Ga1-xAlxAs epitaxial layer and improves the output power of infrared LEDs. The epitaxial layers according to the present invention are (1) a 20-100 mu m thick N-type GaAs epitaxial layer consisting of N-type GaAs doped with Si and having a carrier concentration in the range of from 1.0x1017.cm-3 to 2.0x1018.cm-3, (2) a 10-80 mu m thick P-type GaAs epitaxial layer consisting of P-type GaAs doped with Si and having a carrier concentration in the range of from 1.0x1017.cm-3 to 5.0x1018.cm-3, and (3) a 5-90 mu m thick mixed crystal layer consisting of P-type Ga1-xAlxAs mixed crystal and having a carrier concentration of from 1.0x1017.cm-3 to 5.0x1018.cm- 3, the mixed crystal ratio of Ga1-xAlxAs being in the range of from 0.03 to 0.8 at least in a region of the mixed crystal layer, which is at least 2 mu m thick when measured from the interface between the mixed crystal layer and the P-type GaAs epitaxial layer.