Semiconductive GaAs wafer and method of making the same
View Patent ↗A semiconductive GaAs wafer has a diameter of 4 inches or more, and an in-wafer plane dislocation density of 30,000/cm 2 or more and 100,000/cm 2 or less. A semiconductive GaAs wafer is made by growing a GaAs single crystal under a temperature gradient of 20° C./cm or more and 150° C./cm or less formed in the crystal so that the semiconductive GaAs wafer has an in-wafer plane dislocation density of 30,000/cm 2 or more and 100,000/cm 2 or less.
1. A semiconductive GaAs wafer comprising:
a diameter of 4 inches or more;
an in-wafer plane dislocation density of 30,000/cm 2 or more and 100,000/cm 2 or less; and
an in-wafer plane residual strain value |Sr−St| of 1.8×10 −5 or less, where the in-wafer plane residual strain valve |Sr−St| is measured by using a photoelastic phenomenon that a polarization plane is rotated according to a intensity of a stress.
2. A method of making a semiconductive GaAs wafer, comprising:
growing a GaAs single crystal under a temperature gradient of 20° C./cm or more and 150° C./cm or less formed in the crystal so that the semiconductive GaAs wafer comprises an in-wafer plane dislocation density of 30,000/cm 2 or more and 100,000/cm 2 or less.
3. The method according to claim 2 , further comprising:
annealing the GaAs single crystal after the GaAs single crystal growing step.
4. The method according to claim 3 , wherein:
the annealing comprises a maximum attained temperature of 900° C. or more and 1150° C. or less so that the semiconductive GaAs wafer comprises an in-wafer plane residual strain value |Sr−St| of 1.8×10 −5 or less.