A structure for a semiconductor device includes a copper (Cu) layer and a first nickel (Ni) alloy layer with a Ni grain size a.sub.1. The structure also includes a second Ni alloy layer with a Ni grain size a.sub.2, wherein a.sub.1<a.sub.2. The first Ni alloy layer is between the Cu layer and the second Ni alloy layer. The structure further includes a tin (Sn) layer. The second Ni alloy layer is between the first Ni alloy layer and the Sn layer.

A structure for a semiconductor device includes a copper (Cu) layer and a first nickel (Ni) alloy layer with a Ni grain size a.sub.1. The structure also includes a second Ni alloy layer with a Ni grain size a.sub.2, wherein a.sub.1<a.sub.2. The first Ni alloy layer is between the Cu layer and the second Ni alloy layer. The structure further includes a tin (Sn) layer. The second Ni alloy layer is between the first Ni alloy layer and the Sn layer.

A semiconductor package includes a plurality of semiconductor chips on a substrate. The semiconductor chips include a first semiconductor chip, a second semiconductor chip, and a third semiconductor chip that are sequentially stacked on the substrate. The semiconductor package further includes a plurality of non-conductive layers between the substrate and the first semiconductor chip and between adjacent semiconductor chips among the semiconductor chips. The semiconductor chips include smaller widths as a distance from the substrate increases. Each of the non-conductive layers includes an extension protruding outward from a side surface of an overlying one of the semiconductor chips.

Various embodiments of the present application are directed towards a method for forming an integrated chip in which a group III-V device is bonded to a substrate, as well as the resulting integrated chip. In some embodiments, the method includes: forming a chip including an epitaxial stack, a metal structure on the epitaxial stack, and a diffusion layer between the metal structure and the epitaxial stack; bonding the chip to a substrate so the metal structure is between the substrate and the epitaxial stack; and performing an etch into the epitaxial stack to form a mesa structure with sidewalls spaced from sidewalls of the diffusion layer. The metal structure may, for example, be a metal bump patterned before the bonding or may, for example, be a metal layer that is on an etch stop layer and that protrudes through the etch stop layer to the diffusion layer.

Various embodiments of the present application are directed towards a method for forming an integrated chip in which a group III-V device is bonded to a substrate, as well as the resulting integrated chip. In some embodiments, the method includes: forming a chip including an epitaxial stack, a metal structure on the epitaxial stack, and a diffusion layer between the metal structure and the epitaxial stack; bonding the chip to a substrate so the metal structure is between the substrate and the epitaxial stack; and performing an etch into the epitaxial stack to form a mesa structure with sidewalls spaced from sidewalls of the diffusion layer. The metal structure may, for example, be a metal bump patterned before the bonding or may, for example, be a metal layer that is on an etch stop layer and that protrudes through the etch stop layer to the diffusion layer.

A method of forming a bonding element including a first transient liquid phase (TLP) bonding element including a first material and a second material, the first material having a higher melting point than the second material, a ratio of a quantity of the first material and the second material in the first TLP bonding element having a first value, and a second TLP bonding element including the first material and the second material, a ratio of a quantity of the first material and the second material in the second TLP bonding element having a second value different from the first value.

A method of forming a bonding element including a first transient liquid phase (TLP) bonding element including a first material and a second material, the first material having a higher melting point than the second material, a ratio of a quantity of the first material and the second material in the first TLP bonding element having a first value, and a second TLP bonding element including the first material and the second material, a ratio of a quantity of the first material and the second material in the second TLP bonding element having a second value different from the first value.

A bonding element includes a first transient liquid phase (TLP) bonding element including a first material and a second material, the first material having a higher melting point than the second material, a ratio of a quantity of the first material and the second material in the first TLP bonding element having a first value and a second TLP bonding element including the first material and the second material, a ratio of a quantity of the first material and the second material in the second TLP bonding element having a second value different from the first value.

A bonding element includes a first transient liquid phase (TLP) bonding element including a first material and a second material, the first material having a higher melting point than the second material, a ratio of a quantity of the first material and the second material in the first TLP bonding element having a first value and a second TLP bonding element including the first material and the second material, a ratio of a quantity of the first material and the second material in the second TLP bonding element having a second value different from the first value.

Various embodiments of the present application are directed towards a method for forming an integrated chip in which a group III-V device is bonded to a substrate, as well as the resulting integrated chip. In some embodiments, the method includes: forming a chip including an epitaxial stack, a metal structure on the epitaxial stack, and a diffusion layer between the metal structure and the epitaxial stack; bonding the chip to a substrate so the metal structure is between the substrate and the epitaxial stack; and performing an etch into the epitaxial stack to form a mesa structure with sidewalls spaced from sidewalls of the diffusion layer. The metal structure may, for example, be a metal bump patterned before the bonding or may, for example, be a metal layer that is on an etch stop layer and that protrudes through the etch stop layer to the diffusion layer.