SEMICONDUCTOR DEVICE, METHOD OF MANUFACTURING SEMICONDUCTOR DEVICE, AND METHOD OF RECYCLING SUBSTRATE

In one embodiment, a method of manufacturing a semiconductor device includes forming a first semiconductor layer including impurity atoms with a first density, on a first substrate, forming a second semiconductor layer including impurity atoms with a second density higher than the first density, on the first semiconductor layer, and forming a porous layer resulting from porosification of at least a portion of the second semiconductor layer. The method further includes forming a first film including a device, on the porous layer, providing a second substrate provided with a second film including a device, and bonding the first and second substrates to sandwich the first and second films. The method further includes separating the first and second substrates from each other such that a first portion of the porous layer remains on the first substrate and a second portion of the porous layer remains on the second substrate.