Semiconductor devices with bonding structures and methods for forming the same

A semiconductor device, comprising:

• a first semiconductor structure, a bonding structure, and a second semiconductor structure stacked along a first direction, wherein:
• the first semiconductor structure is bonded to the second semiconductor structure through the bonding structure;
• the bonding structure comprises contact structures and a dielectric material isolating the contact structures from one another;
• and
• a first contact structure of the contact structures is conductive and comprises a first portion comprising a conductive material, a second portion comprising the conductive material, and a third portion being between the first portion and the second portion along the first direction and comprising the conductive material and an oxide.

A method, comprising:

• forming a first semiconductor structure;
• forming a second semiconductor structure;
• and
• forming a bonding structure between the first semiconductor structure and the second semiconductor structure along a first direction to bond the first semiconductor structure to the second semiconductor structure, wherein forming the bonding structure comprises:
• forming a first group of contact structures and a second group of contact structures of the bonding structure, wherein:
• a dielectric material of the bonding structure surrounds the first group of contact structures and the second group of contact structures;
• a first contact structure of the first group of contact structures is adjacent to a second contact structure of the second group of contact structures along a second direction perpendicular to the first direction;
• the first contact structure comprises a first conductive material;
• and
• the second contact structure comprises the first conductive material and a first oxide.