| 摘要 |
1,262,544. Semi-conductor devices. TEXAS INSTRUMENTS Inc. 1 May, 1969 [10 May, 1968], No. 22234/69. Heading H1K. An ohmic contact to a zone of a semi-conductor device or integrated circuit comprises a layer of rhenium overlaid by a layer of high conductivity metal. The integrated circuit of Fig. 5 is formed from a P-type Si wafer by planar diffusion steps to form first the N-type zones 31, 35, then the P zones 32, 34, thirdly the N+ collector contact and emitter zones 36, 33 and finally the boron diffused P + base contact zone 38 and resistance contact zones 39, 40. On the appropriately apertured oxide layer 37 rhenium, gold or copper, and rhenium layers are successively deposited by evaporation or R.F. sputtering and shaped by photoresist and etching steps, using specified etchants, to provide the contacts and interconnections shown. After deposition of a further oxide layer 43 apertures are etched to expose certain of the interconnections and contacts as at X, where rhenium is then removed and replaced by superposed layers of rhenium and gold which are etched to form a desired interconnection pattern as before. Ohmic contacts with expanded bonding pads can similarly be provided on passivated planar transistors in a common slice from which single devices can be divided. In this case platinum may first be deposited on the contact areas and heated to form platinum silicide prior to deposition of rhenium and gold layers. Contact resistance is lowest when the contact areas are heavily P or N doped (>10<SP>21</SP> atoms/c.c.) or precoated with aluminium. |
