Angled wafer rotating ion implantation
View Patent ↗Ion implantation by mounting a semiconductor wafer on a rotating plate that is tilted at an angle relative to an ion implantation flux. The tilt angle and the ion implantation energy are adjusted to produce a desired implantation profile. Ion implantation of mesa structures, either through the semiconductor wafer's surface or through the mesa structure's wall is possible. Angled ion implantation can reduce or eliminate ion damage to the lattice structure along an aperture region. This enables beneficial ion implantation profiles in vertical cavity semiconductor lasers. Mask materials, beneficially that can be lithographically formed, can selectively protect the wafer during implantation. Multiple ion implantations can be used to form novel structures.
1. An ion-implanted semiconductor device comprising:
a substrate layer;
a first layer formed over the substrate layer, the first layer including an active layer;
a mesa structure formed over the first layer, at least a portion of the mesa structure having a substantially rectangular crosssectional profile; and
an ion implantation region formed in both a portion of the mesa structure and a portion of the first layer, wherein the ion implantation region extends into the portion of the mesa having a substantially rectangular cross-sectional profile.
2. An ion-implanted semiconductor device according to claim 1 , wherein the ion-doped semiconductor device is a vertical cavity surface emitting laser and the mesa structure includes a distributed Bragg reflector.
3. An ion-implanted semiconductor device according to claim 1 , wherein the mesa structure further comprises an aperture defined in part by the ion implantation region and wherein the ion implantation region fanned in the portion of the mesa structure has a wedge-shaped ion-doping cross-sectional profile.
4. Art ion-implanted semiconductor device comprising:
a substrate layer;
a lower layer formed over the substrate layer, the lower layer including an active layer;
an upper layer formed over the lower layer; and
a first ion implantation region and a second inn implantation region, at least a portion of each ion implantation region being defined in the upper layer and/or the lower layer, a non-overlapping portion of the first ion implantation region formed vertically to a non-overlapping portion of the second ion implantation region and the first and second ion implantation regions defining a current confinement region, each of the first and second ion implantation regions having a substantially wedge-shaped ion-doping cross-sectional profile, the first ion implantation region associated with a first ion implantation energy and the second ion implantation region associated with a second ion implantation energy.
5. An ion-implanted semiconductor device according to claim 4 , wherein the ion-doped semiconductor device is a vertical cavity surface emitting laser and the upper layer includes a distributed Bragg reflector.
6. An ion-doped semiconductor device according to claim 5 , wherein the upper layer includes a mesa structure, at least a portion of the mesa structure included in one of the plurality of ion implantation regions.
7. An ion-implanted semiconductor device according to claim 4 , in which at least a portion of each ion implantation region is defined in the upper layer.
8. An ion-implanted semiconductor device according to claim 4 , in which at least one of the wedge shaped profiles farms a point with an acute angle.