High mobility transport layer structures for rhombohedral Si/Ge/SiGe devices
AssigneeUnited States of America as represented by the Administrator of NASA
InventorsSang Hyouk Choi, Yeonjoon Park, Glen C. King, Hyun-Jung Kim, Kunik Lee
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Abstract
An electronic device includes a trigonal crystal substrate defining a (0001) C-plane. The substrate may comprise Sapphire or other suitable material. A plurality of rhombohedrally aligned SiGe (111)-oriented crystals are disposed on the (0001) C-plane of the crystal substrate. A first region of material is disposed on the rhombohedrally aligned SiGe layer. The first region comprises an intrinsic or doped Si, Ge, or SiGe layer. The first region can be layered between two secondary regions comprising n+doped SiGe or n+doped Ge, whereby the first region collects electrons from the two secondary regions.
Claims15
A method of fabricating an electronic device, the method comprising:
- providing a trigonal crystal substrate defining a (0001) C-plane;
- applying heat to the trigonal crystal substrate to raise a temperature of the trigonal crystal substrate to a level that facilitates growth of rhombohedrally aligned material;
- growing on the substrate a rhomohedrally aligned buffer layer comprising a material selected from a group consisting of group IV semiconductors and alloys of group IV semiconductors, wherein the rhombohedrally aligned buffer layer comprises a plurality of rhombohedrally aligned (111)-oriented crystals disposed on the (0001) C-plane of the trigonal crystal substrate;
- growing a first region of material on the rhombohedrally aligned buffer layer, the first region comprising a p+doped SiGe layer having a thickness of less than about 100 nm;
- and
- growing a secondary region on the first region, the secondary region comprising a p−doped Ge or intrinsic Ge material to form a quantum well structure for fast transport of holes such that the secondary region collects holes from the first region.
A method of fabricating an electronic device, the method comprising:
- providing a trigonal crystal substrate defining a (0001) C-plane;
- applying heat to the trigonal crystal substrate to raise a temperature of the trigonal crystal substrate to a level that facilitates growth of a rhombohedrally aligned material selected from a group consisting of Si and SiGe;
- growing a layer of buffer material on the trigonal crystal substrate, the layer of buffer material selected from a group consisting of group IV semiconductors and alloys of group IV semiconductors, the layer of buffer material including a plurality of rhombohedrally aligned (111)-oriented crystals disposed on the (0001) C-plane of the trigonal crystal substrate;
- growing a first region of material on the layer of buffer material, the first region comprising an intrinsic or doped first semiconductor material selected from a group consisting of Si, Ge, and SiGe, the first region comprising a first layer of SiGe material with p+doped SiGe;
- growing a layer of Ge material including p−doped Ge or intrinsic Ge on the first layer of SiGe material with p+doped SiGe;
- and
- growing a second layer of SiGe material with p+doped SiGe on the layer of Ge material such that the layer of Ge material is disposed between the first and second layers of SiGe material with p+doped SiGe.
Dependencies are inferred from the claim text.