Silicon Etch Processing

Recently, the nanoFAB installed and qualified a new, state-of-the-art silicon etch system from Oxford Instruments.  The Oxford Estrelas ICPRIE system is capable of performing high-rate Si etch processes using the switched Bosch process, as well as thin-film silicon etches on the nanometre scale.  Also equipped is a cryogenic process, in which smooth sidewalls are obtained by etching using SF₆ and O₂ at cryogenic temperatures.

Below are some SEM images depicting examples of typical Si etch processes performed using the Estrelas; more details about these processes can be found here.  For further information or to enquire about tool usage, please contact Aaron Hryciw (


Bosch Deep Si Etching


High-rate (left) and smooth-sidewall (right) Bosch processes available for deep Si etching.


Bosch Etching Effects

ARDE and Sidewall

Aspect ratio dependent etch rate (left) and sidewall scallops (right).


Unswitched Si Etching

Unswitched and Cryo2

Use an unswitched etch process for thin Si device layers where sidewall smoothness is paramount.