Shoulder the task of the high speed large capacity communication revolutionary device ~ "GaN HEMT" in the course of the development of ~ (2)
Using the principle of "HEMT", to develop new devices
"HEMT" idea is from the space admiral transistor electronic occurred within the layer structure of the region and the free zone phase separation, "GaN HEMT" on this basis, in the electronic layer used in aluminum gallium nitride (AlGaN), used in electronic ionospheric gallium nitride (GaN).Substrate by using silicon carbide (SiC) have excellent thermal conductivity, when running the transistor, its structure is conducive to efficient heat dissipation.In the SiC substrate, through a technique known as the "epitaxial growth, the growth of GaN and AlGaN single crystal film, finally attach electrodes, and made the" GaN HEMT ".
When facing the first issue is SiC is very expensive, and it is difficult to obtain.Based on the technology of epitaxial single crystal film growing need of appropriate conditions, the optimal conditions, and how to set the this step also fell into dilemma.Even solve these issues, how to ensure the reliability of it is not easy.Although show higher values in pressure, but in the process of voltage after the power, "GaN HEMT" is very easily damaged.In the process of exploring reasons, researchers found the quality problem of the SiC as substrate.In order to ensure reliability, research and development personnel and related parties work together to promote the various measures, such as, through close collaboration with SiC substrate manufacturers, improve the quality of the substrate.In the electronic device of SEDI now first development department is responsible for the design and development of customized a history of the transistor's eight volumes, was for the development of "GaN HEMT" and a member of the team that struggled mightily.
"How to improve the low yield?To let the customer USES the product, there is no tangible results must be effectively ensure the quality.In can't find the causes of poor, and there is no answer, we still adhere to explore, to seek the answer.Then, we developed a unique screening technology.This means that we established can accurately find out the bad product and eliminate screening method.We did not stop to pure produced, more importantly, we thoroughly implement the attaches great importance to quality."(8)
In order to ensure that the trust from clients
In solving difficulties and promote development at the same time, the staff also conducted to promote the "GaN HEMT" of the business activities of cognition and enlightenment (for example: "GaN HEMT" samples).One of its head is now in Hong Kong sumitomo electric (Asia) co., LTD. President sang exhibition weeks.
"GaN HEMT has a very high characteristics, but the need to use, to the actual experience.We invite developers to actual measurement of numerous customers, in order to promote to GaN HEMT understanding and carrying out the work.In addition, GaN HEMT is a 50 v high voltages to giving full play to the advantages of the device, but at the time no 50 v products in base station power supply parts.While power producers are not customers, but we still take the initiative to conduct technical exchanges, with in the process, please manufacturers developed a 50 v power supply, and realizes the transition.In this way, we are building GaN HEMT related market conditions at the same time, with its business into a target, carry out the business activities.More importantly, we introduced the digital distortion compensation technology.Digital distortion compensator for the input signal, eliminate the distortion resulting from the amplifier, is an important technology in the base station, it can ensure the quality of the communication, to achieve low power operation.
After for Si - the use of LDMOS is optimized, so when we showed the customer is suitable for the characteristic of GaN distortion compensation measure sample.By this effort, we can let the customer understand GaN HEMT features and advantages."(change)
Changes of enlightenment and business activities is not limited to domestic, also involved in North America, Europe and Asia, "GaN HEMT" in the global market right from the start.Under such a move, shipment samples, 2005, in 2006 began to mass production, the products used in Japan in 2007 domestic 3 g base stations.SEDI throughout the world take the lead to achieve the "GaN HEMT" transition.
Early in the "GaN HEMT" development, the SEDI did not use labor division system (development, manufacturing, and business), but "ONETEAM" system is adopted to carry out work.
"At that time, in the competition to Si - LDMOS in this matter, our heart is unwilling to all members, and strongly want to GaN HEMT as base station device on the market after the implementation stage a come back."(change)
Although SEDI implements the "world first", but in the process of start, issue is still there.Although the yield has been improved to a certain, but the price is always high.In Japan, people to "GaN HEMT" excellent low power operation are cognitive, also have many clients use the transistor, but even so, the world market is still preferred choice as its rivals device - "Si - LDMOS".GaN HEMT shipments to respond.Under such conditions, SEDI technology team began to low cost.
