Semiconductor Memories｜Basic

What is Semiconductor Memory?

table of contents

・Semiconductor Memory Types
・Characteristics of Various Types of Memory

Semiconductor memory is a type of semiconductor device tasked with storing data. There are two electronic data storage mediums that we can utilize, magnetic or optical.

Magnetic storage:

Stores data in magnetic form.
Affected by magnetic fields.
Has high storage capacity.
Doesn’t use a laser to read/write data.
Magnetic storage devices are; Hard disk , Floppy disk, Magnetic tape etc.

Optical storage:

Stores data optically, uses laser to read/write.
Not affected by magnetic fields.
Has less storage than a hard disk.
Data accessing is high, compared to a floppy disc.
Optical storage devices are; CD-ROM,CD-R, CD-RW, DVD etc.

There is also volatile memory. This is memory that loses its data once power is cut off, while non-volatile memory retains data even without power.

Semiconductor Memory Types

* RAM (Random Access Memory) : Enables Read/Write of stored contents

* ROM (Read Only Memory) : Allows only Read operation

Characteristics of Various Types of Memory

Parameter	RAM			ROM
	Volatility		Non Volatility
	SRAM	DRAM	FeRAM	Mask ROM	EPROM	EEPROM	FLASH
Data Storage Method	Voltage Bias	Voltage Bias + Refresh	Unnecessary
No. of Read Operations	∞	∞	10 billion to 1 trillion times	∞	∞	∞	∞
No. of Rewrites	∞	∞	10 billion to 1 trillion times	0 times	100 times	100,000 to 1 million times	10,000 to 100,000 times
Write on Substrate	Possible	Possible	Possible	×	×	Possible	Possible
Read Time	◎	◎	○	○	○	○	○
Write Time	◎	◎	○	–	△	△	△
Bit Cost	△	○	△	◎	△	△	◎
Larger Capacity	○	◎	△	◎	△	△	◎
Memory Cell	Stored in a flip flop circuit	Maintains charge in the capacitor	Polarization of the ferroelectric material	Ions implanted in a transistor	Maintains charge in the floating gate	Maintains charge in the floating gate	Maintains charge in the floating gate

electronics-basics

Semiconductor Memories

Basic

What is Semiconductor Memory? ＋