Epitaxy for growing compound semiconductors and an InP substrate for epitaxial growth

摘要

Hillocks arise on the films, when compound semiconductor films are grown on an InP wafer having a surface near a (100) orientation. Off-angle wafers have been adopted for a substrate in order to suppress the occurrence of hillocks. The off-angle THETA from a (100) plane is not a sole factor for ruling the generation of hillocks. There is a concealed parameter which determines the generation of hillocks. What induces hillocks on the growing film is the defects on the substrate itself. No hillocks originate on a part of an InP wafer without dislocations. The role of the off-angle THETA of the substrate is preventing the influence of the dislocations from transmitting to the films. A smaller density D of the defects on the substrate allows a smaller off-angle THETA for suppressing the hillocks from arising. A bigger density D of the defects demands a larger off-angle for the substrate so as to forbid the hillocks from originating. An inequality THETA >/= 1 x 10<-><3>D<1/2> is the condition for annihilating hillocks. More precise condition is THETA >/= 1.26 x 10<-><3>D<1/2>. $$