Si and SiGe Alloys Wet Etching Using TMAH Chemistry

From MEMS to CMOS applications, silicon wet anisotropic etching is nowadays considered as an interesting alternative to face new and various technological challenges. This paper focuses on the TMAH chemistry and its use for Si and Si1-xGex alloys etching. Comparing two different dispense modes (immersion and spin-on), the impact of TMAH experimental conditions on the etching kinetics as well as on the surface morphology is discussed. We demonstrated that alleviating TMAH-induced Si surface degradation can be obtained by transferring the TMAH etching process on a spray dispense tool. We also highlight the drastic impact of germanium incorporation on the silicon etch rate which opens the scope to TMAH for many applications.