How does semiconductor memory enable data storage?

Data is stored with two different potentials, high and low.

Semiconductor memory (semi-conductor memory) is a kind of memory that uses semiconductor circuits as storage, and internal memory is composed of semiconductor integrated circuits called memory chips.

According to its function, it can be divided into: random access memory (referred to as RAM) and read-only memory (read-only ROM).

RAM includes DRAM (Dynamic Random Access Memory) and SRAM (Static Random Access Memory), and information is lost when the power is shut down or power is off. DRAM is mainly used for main memory (the main part of memory), and SRAM is mainly used for cache memory, ROM

Mainly used for BIOS memory.

According to its manufacturing process, it can be divided into: bipolar transistor memory and MOS transistor memory.

According to its storage principle, it can be divided into two types: static and dynamic.

Its advantages are: small size, fast storage speed, high storage density, and easy interface with logic circuits.

It is mainly used as cache memory, main memory, read-only memory, stack memory, etc.

The technical indicators of semiconductor memory mainly include:

3.Access Period: The minimum amount of time between two independent memory operations.

4.Mean Time Between Failures MTBF (Reliability).

5.Power consumption: dynamic power consumption, static power consumption.

Semiconductor memory chips can be divided into two categories: read only memory (ROM) and random access memory (RAM) according to the read and write function.

The read-only memory circuit structure is simple, and the stored data will not be lost after power failure, especially suitable for storing permanent, unchanging programs or data (such as constant tables, functions, ** and characters, etc.), and the self-test program in the computer is solidified in the ROM. The biggest advantage of ROMs is that they are not volatile.

Non-rewritable read-only memory.

1. Mask read-only memory (MROM).

Mask read-only memory, also known as fixed ROM. When this kind of ROM is manufactured, the manufacturer uses mask technology to write the information into the memory, and the user cannot change it when it is used, so it is suitable for mass production.

Mask read-only memory can be divided into three types: diode ROM, bipolar triode ROM, and MOS ROM.

2. Programmable read-only memory (PROM).

Programmable ROM (PROM) is a read-only memory that can be written by the user at one time, and is developed on the basis of MOM.

Random read-write memory

1. Static memory (SRAM).

The bistable trigger is used to save information, and the information will not be lost as long as it is uninterruptible. Static memory has low integration, high cost, and high power consumption, and is usually used as a cache storage body.

2. Dynamic memory (DRAM).

The MOS capacitor is used to store the charge to save information, and the capacitor needs to be continuously charged to maintain the information during use. The dynamic memory circuit is simple, the integration is high, the cost is low, and the power consumption is small, but it needs to be refreshed repeatedly, and the working speed is slow, so it is suitable as the main part of the main memory.

3. Enhanced DRAM (EDRAM).

The EDRAM chip is composed of a high-speed and small-capacity SRAM chip integrated on the DRAM chip, and the small-capacity SRAM chip acts as a high-speed cache, so that the performance of the DRAM chip is significantly improved.

Classification of semiconductor memory: RAM and ROM

There are two kinds of RAM, SRAM (static RAM), which uses a flip-flop circuit to form a binary bit information storage unit, this flip-flop is generally composed of 6 transistors, it reads out using the principle of unilateral readout, and writes using the principle of bilateral write-in; DRAM (dynamic RAM), which has a high degree of integration, and the internal storage units are arranged into a storage body in the form of a rectangular array, and usually adopts the composite selection addressing method of row and column addresses.

There are 5 types of ROMs, fixed mask programmable ROM, programmable PROM, UV sassafras programmable EPROM, electrically sassafrass programmable EPROM, flash memory.

The storage medium of memory is semiconductors, which are generally called semiconductor memoryIt is composed of a large number of identical memory cells and input and output circuits. Each memory cell has two different representations, 0 and 1, to store different information. Semiconductor memory is an important part of a computer.

Compared with magnetic memory Tantan, semiconductor memory has the advantages of fast access speed, large storage capacity, small size, etc., and the memory cell array is compatible with the main external peripheral logic circuit, which can be made on the same chip, so that the input and output interfaces are greatly simplified.

Classification of semiconductor memories.

According to different functions, semiconductor memory can be divided into three categories: random memory (RAM), read-only memory (ROM), and serial memory. With the development of semiconductor integrated circuit process technology, the capacity of semiconductor memory has grown very rapidly, and the monolithic memory capacity has entered the megabit level, such as 16 trillion dynamic random access memory (DRAM) has been commercialized, and 64 trillion and 256 trillion DRAM are under development.

There are mainly the following types of semiconductor memory components that make up the internal memory:

Dynamic Random Access Memory (DRAM) :d RAM is a capacitor-based memory that is characterized by a small memory cell, high integration, and fast read and write speed, but it needs to be refreshed regularly and has a short storage time.

Static Random Access Memory (SRAM): SRAM is a trigger-based memory that is characterized by large memory cells, low integration, fast read and write speeds, and does not require refreshes, but has high power consumption and high cost.

Flash memory: Flash memory is a non-volatile spring memory, which is characterized by small storage cells, high integration, fast read and write speeds, and limited erase times, which is suitable for large-capacity storage.

Read-only memory (ROM): ROM is a type of read-only memory that is characterized by a large memory cell, low integration, and fast read speed, but it cannot be modified.

The above memory components are widely used in computers and other electronic equipment, and different memory components have different characteristics and applications, which can be selected according to specific application requirements.

Pro,1 Semi-conductive dendritic memory is an important part of modern digital systems, especially computers, which can be divided into two categories: RAM and ROM, and most of them belong to large-scale integrated circuits made by MOS process. 2 RAM is a sequential logic circuit with a memory function. The data it stores disappears when the power supply is cut off, so it is a volatile read-write memory.

It consists of two types: SRAM, which uses a flip-flop to remember data, and DRAM, which stores data by MOS gate capacitors. As a result, SRAM data can be maintained for a long time without power outage, while DRAM must be refreshed regularly. 3 ROM is a non-volatile memory that stores fixed data and can only be read out.

According to the different ways of data writing, ROMs can be divided into fixed ROMs and programmable ROMs. Hope it helps.

1. Random access.

A memory that reads and writes data at the same speed, at the same speed, randomly at the same speed (the write speed and readout speed can be different). The internal structure of the memory unit is generally composed of a two-dimensional square matrix, that is, the form of one bit and one address (such as 64k 1 bit). However, sometimes there is also a form that is orchestrated to facilitate multi-bit output (e.g. 8k 8-bit).

Features: This type of memory is characterized by a small number of cell devices, a high degree of integration, and is the most widely used (see Metal-Oxide-Semiconductor Dynamic Random Access Memory).

2. Read-only memory.

It is used to store long-term fixed data or information, such as various function tables, characters, and fixed programs. The unit has only one diode or triode. As a general rule, it is "1" when the device is turned on, "0" when it is disconnected, and vice versa.

When designing a read-only memory mask, the data is written in the reticle pattern, and then transferred to the silicon chip during lithography.

Features: Its advantage is that it is suitable for mass production. However, in the debugging stage of the whole machine, it is often necessary to modify the content of the read-only memory, which is time-consuming, troublesome, and inflexible (see Semiconductor read-only memory).

3. Serial memory.

Its cells are arranged in a one-dimensional structure, like a magnetic tape. The first and last sections are read long apart because the entire tape is passed sequentially. The cells in semiconductor serial memory are also arranged in one dimension, and the data is read sequentially in each column, such as shift registers and charge-coupled memory.

Features: GaAs semiconductor memories such as 1024-bit static random access memory (RRAM) have a read time of 2 milliseconds, and are expected to develop in the ultra-high-speed field.