The transistor used in DRAM is a Metal Oxide Semiconductor Field Effect Transistor (MOSFET).
Understanding the DRAM Cell
A fundamental unit of Dynamic Random-Access Memory (DRAM) is the memory cell. As highlighted in the provided reference, each DRAM cell is composed of two primary components:
- A transistor: This acts as a switch to control access to the storage element.
- A capacitor: This stores the data as an electrical charge.
The presence or absence of a charge on the capacitor determines the logical state of the cell:
- Absence of charge = logic "0"
- Presence of charge = logic "1"
The Role of the MOSFET in DRAM
Specifically, the transistor used in this simple one-transistor/one-capacitor (1T1C) DRAM cell structure is a MOSFET.
The MOSFET in a DRAM cell functions primarily as a gate or a switch. It allows the data (charge) to be written into the capacitor or read out from it.
- Writing Data: When writing data, a voltage is applied to the gate of the MOSFET, turning it "on." This allows charge to flow through the transistor to either charge or discharge the capacitor, storing a '1' or a '0'.
- Reading Data: When reading data, the MOSFET is turned "on" again, allowing the charge stored on the capacitor to influence the voltage on a sense line. This voltage is then amplified and interpreted as a '1' or a '0'.
Once the read or write operation is complete, the voltage on the MOSFET's gate is removed, turning the transistor "off" and isolating the capacitor, preserving the stored charge.
Components of a DRAM Cell
Here's a simple representation of the core components:
| Component | Role |
|---|---|
| MOSFET | Acts as a switch |
| Storage Capacitor | Stores the data (charge) |
This simple 1T1C structure, utilizing a MOSFET as the control element, is the basis for the high density achieved in modern DRAM chips.
