One-Transistor Cell for Area Reduction

The question asks for a memory cell approach that minimizes the physical area occupied per bit of storage. This approach involves a storage capacitor, denoted as $C_m$, which gets charged via a 'read/write' line when the 'row select' line is active (high).

Understanding the One-Transistor DRAM Cell

This description precisely matches the structure and operation of a standard Dynamic Random Access Memory (DRAM) cell, commonly known as the one-transistor cell.

• Components: It consists of a single access transistor and a storage capacitor ($C_m$).
• Operation: The transistor acts as a switch. When the 'row select' line is high, the transistor turns on, connecting the storage capacitor $C_m$ to the bit line ('read/write' line).
• Write Operation: During a 'write' operation, data is transferred onto the bit line, and the capacitor $C_m$ is charged or discharged accordingly through the activated transistor.
• Density Advantage: This simple structure (1T + 1C) is highly scalable and requires significantly less area compared to other RAM cell types like SRAM (which typically uses six transistors), leading to a lower area per bit requirement.

Evaluating Other Options

• Two-transistor, Three-transistor RAM cells: These are not standard configurations for high-density memory like DRAM.
• Six-transistor cell: This is the standard cell structure for Static RAM (SRAM). While faster, SRAM cells occupy a much larger area per bit compared to DRAM cells, contradicting the goal mentioned in the question.

Therefore, the one-transistor cell is the approach used to reduce the area per bit requirement using the described mechanism.