| 摘要 |
An MOS/LSI type dynamic RAM with single 5 V supply and grounded substrate employs a guard ring surrounding the cell array to prevent pattern sensitivity in testing. The guard ring is an N+ region biased at Vdd over a deep P+ region in a P-substrate, producing a built-in electric field which attracts diffusing minority carriers into a collecting junction. A standard process for making double-level poly memory devices is modified by adding a P+ implant and deep drive-in prior to field oxidation. |
