Title :
A large cell-ratio and low node leak 16 M-bit SRAM cell using ring-gate transistors
Author :
Yuzuriha, K. ; Kuriyama, H. ; Okada, T. ; Tsutsumi, K. ; Tokui, A. ; Sugahara, K. ; Higaki, Y. ; Nishimura, T. ; Kohno, Y. ; Tsubouchi, N.
Author_Institution :
Mitsubishi Electric Corp., Hyogo, Japan
Abstract :
An advanced memory cell for a 16-Mb SRAM (static RAM) has been developed. The cell has ring-shaped gate electrode (ring-gate) driver transistors and PMOS TFT (thin film transistor) loads utilizing steps of underlayers. The ring-gate driver transistors achieve more than 3.2 large cell-ratio ( beta r) which is free from misregistration, and also 2-fA low-leakage current of the memory cell node. The titanium silicided source region (Rs=7 Omega / Square Operator ) of driver transistors is common to both in a cell, so there is little imbalance of the ground line. The 14-fA off-current (Vd=3 V, Vg=0 V) of the TFT makes possible less than 0.3- mu A standby current in a 16-Mb SRAM. It is noted that these device characteristics will certainly make it possible to fabricate a 16-Mb SRAM with this cell.<>
Keywords :
CMOS integrated circuits; SRAM chips; leakage currents; 0.3 muA; 16 Mbit; 2 fA; PMOS TFT; SRAM cell; TFT loads; TiSi/sub 2/ contact; driver transistors; large cell-ratio; low node leak; low-leakage current; memory cell; ring-gate transistors; ring-shaped gate electrode; silicided source region; static RAM; thin film transistor; Batteries; Driver circuits; Electrodes; Laboratories; Large scale integration; Leakage current; Random access memory; Thin film transistors; Titanium; Voltage;
Conference_Titel :
Electron Devices Meeting, 1991. IEDM '91. Technical Digest., International
Conference_Location :
Washington, DC, USA
Print_ISBN :
0-7803-0243-5
DOI :
10.1109/IEDM.1991.235350
