High current density, low contact resistance wide bandgap contacts
| DWPI Title: Semiconductor device e.g. high electron mobility transistor for use in high-power application, has high perimeter length contact which is formed with total perimeter length two times greater than length of side of contact pad |
| Abstract: A high current density, low contact resistance contact for wide bandgap (WBG) or ultra-wide bandgap materials (UWBG) is disclosed. The contact is lithographically formed so that a total perimeter length of the contact structure is at least twice the length of the side of a contact pad closest to the gate in a high electron mobility transistor (HEMT). The contact structure may take the form of a plurality of columns having various cross-sectional shapes, or may take the form of a convoluted geometrical shape, such as a comb-like, serpentine, or spiral shape. The depth of the contact structure permits direct contact with the two-dimensional electron gas (2DEG) in the HEMT by the perimeter of the contact structure. The contact structure is formed of at least one metal layer, at least one doped material regrown layer, or at least one implanted region. The contact structure may be applied to other WBG and UWBG devices. |
| Use: Semiconductor device e.g. high electron mobility transistor (HEMT) such as aluminum gallium nitride (AlGaN)-based HEMT and gallium nitride (GaN)-based HEMT for use in high-power application. |
| Advantage: The direct contact area between the contact and the 2DEG layer in the HEMT can be increased due to the significantly increased perimeter length. The significant surface contact to the 2DEG layer can be realized by employing either a metallization structure or a doped material regrown structure, thus resulting in increased current densities and lower contact resistances. |
| Novelty: The semiconductor device has semiconductor material layers (120A-120D), and a high perimeter length contact which is formed in a top surface (140) of the semiconductor material layer. A contact pad (150) is formed on a top surface of the high perimeter length contact and a first portion of the top surface of the semiconductor material layer and electrically connected to the high perimeter length contact. A gate electrode is formed on a second portion of the top surface of the semiconductor material layer. The second portion of the top surface of the semiconductor material layer different than the first portion of the top surface of the semiconductor material layer is different than the first portion of the top surface of the semiconductor material layer. The gate electrode is formed adjacent to the contact pad. A total perimeter length of the high perimeter length contact is 2 times greater than a length of a side of the contact pad closest to the gate electrode. |
| Filed: 10/30/2018 |
| Application Number: US16175085A |
| Tech ID: SD 14209.0 |
| This invention was made with Government support under Contract No. DE-NA0003525 awarded by the United States Department of Energy/National Nuclear Security Administration. The Government has certain rights in the invention. |
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