Semiconductor memory device with peripheral switching systems - and having additional trough zone to prevent electron injection, for dynamic random access memory

摘要

Semiconductor memory device has a p-semiconductor substrate (1) with a main surface, a memory cell array region with numerous memory cells on the main surface, a switching system connected with this array for writing/readout and peripheral switching system connected to other sections. A first p-trough zone (P2), connected with an input terminal (Vin) for receiving an external input signal, and a first n-trough zone (N2) are formed in the substrate in the peripheral switching region; a second p-trough zone (P1) and a second n-trough zone (N1) are formed in the substrate in the array region; and a third n-trough zone (N3) is formed around other trough zone(s). N1, N2 and N3 are kept at positive potential; P1 at negative or earth potential and P2 at earth potential. USE/ADVANTAGE - Device is a dynamic random access memory (DRAM). Electorn injection into the trough zones is avoided.