Semiconductor device with trench isolation

摘要

A semiconductor device having a shallow trench isolation structure, where the upper part of the trench is broader than its lower part, includes an insulating layer 34 on the sidewalls of the upper part of the trench, another insulating layer 38 buried in the trench for isolating semiconductor devices and low-concentration doped regions near to the upper part of the trench and high-concentration doped regions near to the lower part of the trench. Leakage current is minimised by the provision of a sufficient quantity of the ions in the high-concentration doped regions near to the lower part of the trench, and the narrow width effect is minimized by virtue of the insulating layer on the sidewalls of the upper part of the trench.