Hybrid infrared ray detector with an improved bonding structure between an Si-substrate having integrated circuits and an HgCdTe layer having two-dimensional photodiode arrays and method for fabricating the same

摘要

A hybrid infrared ray detector includes a first semiconductor substrate which has a first thickness and a first elastic coefficient. A buffer layer is provided on the first semiconductor substrate which is made of a first compound semiconductor having a second elastic coefficient larger than the first elastic coefficient and which has a second thickness smaller than the first thickness. An epitaxial layer is provided on the buffer layer. The epitaxial layer is made of a second compound semiconductor having a third elastic coefficient smaller than the second elastic coefficient and larger than the first elastic coefficient and which has a third thickness which is almost the same as the second thickness. Two-dimensional arrays of photodiodes are provided on a surface of the epitaxial layer. First bumps are provided on the photodiodes. Second bumps are provided on the surface of the epitaxial layer. The second bumps are positioned outside the two-dimensional arrays of the photodiodes. A second semiconductor substrate is provided which has integrated circuits, and third bumps positioned to correspond to the first bumps and fourth bumps positioned to correspond to the second bumps. The second semiconductor substrate is bonded via the first to the fourth bumps to the epitaxial layer. The second semiconductor substrate has a fourth thickness which is almost the same as the first thickness, and a fourth elastic coefficient which is almost the same as the first elastic coefficient. The first to fourth thickness and the first to fourth elastic coefficients are determined that a thermal stress caused by cooling the hybrid infrared ray detector is concentrated within the buffer layer.