Methods of forming an electrical contact to semiconductive material

摘要

A method of forming an electrical contact to semiconductive material includes forming an insulative layer over a contact area of semiconductive material. A contact opening is etched through the insulative layer to the semiconductive material contact area. Such etching changes an outer portion of the semiconductive material exposed by the etching. The change is typically in the form of modifying crystalline structure of only an outer portion from that existing prior to the etch. The changed outer portion of the semiconductive material is etched substantially selective relative to semiconductive material therebeneath which is unchanged. The preferred etching chemistry is a tetramethyl ammonium hydroxidde solution. A conductive material within the contact opening is formed in electrical connection with the semiconductive material. In another aspect, the changed outer portion is etched with a basic solution regardless of selectivity in the etch relative to semiconductive material therebeneath which is unchanged by the contact opening etch. The preferred conductive material is conductively doped semiconductive material which is formed in the contact opening to be in contact with semiconductive material which is unchanged. Further, the conductive material within the contact opening is preferably void of any silicide material.