Technology A is based on a self-aligned optical wafer stepper lithography with phase shift masks, where the subsequent use of SiN sidewall spacers allows to reduce the gate length to = 120 nm. In an iterative process using dry etching the gate is defined. Typical gate lengths are = 120 nm-500 nm and intended for large scale production using WSi gate metal. It is available on 4 and 6 inch GaAs wafers. Several variations are derived from this technology.