Seed layer structure for growth of III-V materials on silicon

摘要

The present disclosure relates to a structure and method of forming a GaN film on a Si substrate that includes an additional or second high temperature (HT) AlN seed layer, introduced for reducing the tensile stress of GaN on a Si substrate. The second HT AlN seed layer is disposed over a first HT AlN seed layer, and has a low V/III ratio compared to the first HT AlN seed layer. The second HT AlN seed layer has better lattice matching between Si and GaN and this reduces the tensile stress on GaN. The additional HT AlN seed layer further acts as a capping layer and helps annihilate or terminate threading dislocations (TDs) originating from a LT AlN seed layer. The second HT AlN seed layer also helps prevent Si diffusion from the substrate to the GaN film.

主权项

1. A semiconductor device, comprising:
a substrate; a first III-V (group III-group V) seed layer disposed over the substrate, wherein the first III-V seed layer has a first ratio of group V atoms to group III atoms; a second III-V seed layer disposed over the first III-V seed layer, wherein the second III-V seed layer has a second ratio of group V atoms to group III atoms, wherein the first III-V seed layer and the second III-V seed layer meet at a saw-toothed interface; a third III-V seed layer disposed over the second III-V seed layer, wherein the third III-V seed layer has a third ratio of group V atoms to group III atoms, wherein the second ratio is greater than the third ratio so the second III-V seed layer is group-V-poor relative to the third III-V seed layer; and at least one device layer of III-V material disposed over the third III-V seed layer.