Method to reduce device contact resistance using a hydrogen peroxide treatment
 A method for developing a semiconductor device low resistance electrical contact is described. In this process a gate oxide layer followed by a polysilicon layer is deposited on the semiconductor substrate in proximity to the device contact area. It is subsequently patterned with photoresist and etched to produce the desired gate structure. This is followed by a deposited layer of silicon dioxide or silicon nitride (SIN) which is appropriately patterned and etched to form gate isolation spacers. Then a nominal 300 .ANG. layer of silicon nitride (SIN) is deposited followed by a layer of tetraethyl orthosilicate (TEOS) or borophosphosilicate glass (BPSG). The contact area is defined by photolithography, and the passivation layers are etched either by a dry etch such as a RIE process, or a combination of a wet BOE process followed by a dry etch, to form the metal contact holes. Prior to sputtering the contact metal, the contact area is cleaned with a 30 second dip in a BOE solution, followed by a Hydrogen Peroxide (H.sub.2 O.sub.2) dip. This H.sub.2 O.sub.2 cleaning step enables lower device contact resistance for the P+ contact areas. 
Taiwan Semiconductor Manufacturing Company
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Chi-Hung Chai-Der Te-Fu Cheng-Yu
Liao Chang Tseng Chu