Etch Rate Study of Germanium, GaAs and InGaAs: A Challenge in Semiconductor Processing

The Si transistor has dominated the semiconductor industry for decades. However, to fulfill the demands of Moore’s law, the Si transistor has been pushed to its physical limits. Introducing new materials with higher intrinsic carrier mobility is one way to solve this problem. Ge, GaAs and InGaAs are known for their high mobilities and are therefore suitable candidates for replacing Si as a channel material. However, introduction of new materials raises new issues. For Si processing, several steps such as cleaning, etching and stripping are based on wet treatments. The knowledge of etch rates of the semiconductor material is of great importance. In this paper, etch rates of Ge, GaAs and InGaAs in several chemical solutions are studied. A comparison of the etch rates is made between the materials.