Shoulder the task of the high speed large capacity communication revolutionary device ~ "GaN HEMT" in the course of the development of ~ (1)
What is meant by "HEMT"?
Support 5 g era electronics - "GaN HEMT".Introduced the "GaN HEMT" before, let's first take a look at "HEMT", it is based on Japan's high level of technical strength and rich creativity of researchers and remarkable achievements, greatly promoted the information communication technology progress of the Japanese original technology."HEMT" is "High Electron Mobility Transistor (High Electron Mobility Transistor)" acronym, as called, it is a kind of Transistor.In 1948, the United States institute of bell invented the transistor as technology has brought the unprecedented impact in the world.The device is a sign of electronic age kicked off, for the rapid development of electronic technology, led by computer, laid a foundation.One of the functions of the transistor can be amplified signal strength "amplification"."Transistor radio" by transistor amplifier, for example, a weak signal transmission in the air, and then play through the speaker.
At first, people germanium is used to make transistors, but before long, almost all raw materials used in the manufacturing transistors were replaced with high heat resistance of silicon.After entering the 70 s, according to the evolution of the transistor, Japan launched a challenge.The first look at the speed of the electron.Past of the silicon transistor electronic layer and layer are free in the same material, so the electron will hit impurities, leading to the slow speed.In order to solve the issue, Fujitsu research institute developed "HEMT" in 1979, it adopted the compound semiconductor.The device structure is: the electronic layer adopts aluminium gallium arsenide (AlGaAs) and electron ionizing layer using high purity gallium arsenide (GaAs) crystal, forming a bilayer overlap between the two constructs.Through the structure, and can realize high speed and high sensitivity of the electrical signal processing.Since 1985, "HEMT" is used in countries around the world of satellite television broadcasting receivers, to start, as in the fields of microwave and millimeter wave devices (such as: mobile phone terminals, stations, satellite navigation receiver, used to prevent collision of millimeter wave radar, etc.), "HEMT" has become the indispensable components, today, as the basis of support society of information communication technology, it still plays a huge role.On the basis of "HEMT" technical achievement, and it has more excellent material properties of gallium nitride (GaN) combined, and ushered in the "GaN HEMT" was born.Sumitomo electric Device Innovation co., LTD (hereinafter referred to as the SEDI) became the its development and manufacturing bases.
To challenge for the potential of gallium nitride
Technology in the first generation (1 g) period, namely the analog phone era, people USES silicon as high power transistor semiconductor material, and the high power transistors will be used for mobile phone base station amplifier.Then, in the second generation (2 g) technology, the digital began to develop in the early 90 s, sumitomo electric group after fully prepared, will use the gallium arsenide transistor "GaAs FET (GaAs FET)" into the market.In GaAs FET, the electron can be more high-speed mobile (close to silicon in the electronic movement speed of 5 times), and can reduce power consumption, thus high-profile.But then the advent of new transistor "silicon LDMOS (Laterally Diffused Metal Oxide Semiconductor)" (hereinafter referred to as Si LDMOS) in various aspects such as features and price than "gaas fet" has the edge, and swept through the market, has led to the development of the third generation (3 g) technology.Since then, sumitomo electric group of electronic devices in the market competition be eliminated pieces.SEDI on behalf of President banned service long GuChuanYu described the situation as a "lost".
"In the market competition, we lost to Si LDMOS, is literally as" lost ", we got into this business is hard to survival difficult position.In such a crisis, there is the news of the new compound semiconductor, institute was advancing its infrastructure development.It was GaN, the gallium nitride.Its features is much more advantage than silicon and gallium arsenide, has the characteristics of high power and high speed, people look forward to its application in electronic devices.At that time, already have no choice, we take the bunker mentality, began to advance gallium nitride related research and development."(hasegawa)
In 2000, with an eye to GaN potential SEDI technology team set out to develop "GaN HEMT".Now belongs to SEDI manufacturing technology of the west really wong was a member of the development team.
"In the material properties of GaN, one makes us feel shocked, that is very high compression strength (breakdown voltage), is about 10 times that of the silicon.In addition, in the case of rising voltage, as peak electron velocity saturation electronic speed reached 2 times more than silicon.Its advantage is that can run high voltage, and easy to implement efficient operation.In addition, as can rival Si - LDMOS device, we think it has a great potential, for example, consumes only a small amount of electricity can achieve high power, etc."(west)
In the same period, has a person to "gaas transistors" the resurrection of the hard struggle for the goal in research and development of the front, now has become a technology development minister, SEDI he is inoue and filial piety.
"At that time, we hope that through the thorough study of the structure of gallium arsenide can develop its new transistor characteristic to the maximum, to regain the Si - LDMOS take market.Then, based on a thorough research, we didn't know the limit properties of gallium arsenide, participated in the related development of gallium nitride.But that is an unknown unknown world, is a path on the thorns."(inoue)
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Shoulder the task of the high speed large capacity communication revolutionary device
~ "GaN HEMT" the development course of ~ (2)