these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the scope of the invention to those skilled in the art in the drawings the thicknesses of layers and regions are exaggerated for clarity like numbers refer to like elements throughout the present invention relates to improved methods for forming polycide gate structures the methods of the present invention allow the formation of polycide gate structures with reduced sidewall erosion and reduced residue generation in particular when dry etching a ti polycide layer to form a ti polycide gate electrode according to the present invention oxygen gas o 2 is added to chlorine gas cl 2 during the dry etch to reduce sidewall erosion additional etch parameters are discussed in greater detail below for example the dry etch used to form the gate electrodes of the present invention can be performed at a pressure of 2 mtorr while maintaining the temperature at a normal level the following formulas illustrate the chemical reactions which occur when etching titanium silicide using a gas mixture including cl 2 and o 2 according to formulas 1 and 2 when the gas mixture including cl 2 and o 2 is used as an etching gas to etch tisix chlorides e g ticl 4 and sicl 4 and oxides e g tio and sio are produced as byproducts the chlorides such as ticl 4 and sicl 4 produced in formula 1 are volatilized during the etch the non.