SEALED CAVITY SEMICONDUCTOR PRESSURE TRANSDUCERS AND METHOD

摘要

Sealed cavity structures used as pressure transducers are formed on a surface of a semiconductor substrate (20) by, for example, depositing polycrystalline silicon layer (32) from silane gas over relatively large silicon dioxide post (22) and smaller silicon dioxide ridges (27) leading outwardly from post. The polysilicon layer is masked and etched to expose outer edges of ridges and the entire structure is then immersed in etchant which etches out ridges and post but not substrate (20) or deposited polysilicon layer (32). A cavity structure results in which channels (35) are left in place of the ridges and extend from communication with the atmosphere to the cavity (36) left in place of the post. The cavity (36) may be sealed off by deposition of material, which fills up and seals off the channels (35), or by exposing the substrate and structure thereon to oxidizing ambient which results in silicon dioxide growth in the channels sufficient to seal them.