Isolated semiconductor device and production method thereof.

摘要

In a method of producing a semiconductor device, when a device, for example, transistor, is formed in a prescribed region of compound semiconductor layers including a low resistance layer which cannot be insulated by ion implantation, upper layers of the compound semiconductor layers including at least the low resistance layer are formed into a mesa shape by etching, and then ion implantation is performed to the compound semiconductor layers in a region other than the region beneath the mesa structure. Thus, the device formed on the substrate is completely isolated from other regions on the substrate by the mesa-etching and the ion implantation. In the structure thus obtained, a level difference on the substrate due to the device is within a range that does not adversely affect the subsequent process steps, for example, a step of producing electrodes. In addition, materials and compositions of the compound semiconductor layers isolated by the mesa-etching are selected according to desired device characteristics without palying considerations on the insulation by ion implantation. Therefore, a degree of freedom in selecting materials and compositions of the compound semiconductor layers formed on the semiconductor substrate increases, resulting in a high-performance device.