Site: Sony Corporation Research Center
174, Fujitsuka-cho, Hodogaya-ku
Yokohama-shi, 240 Japan

Date Visited: November 18, 1994

Report Author: D. Keck

ATTENDEES

JTEC:

S. Esener
D. Keck

HOSTS:

Dr. Jun'etsu Seto
Senior General Manager, Materials Research Division
Dr. Yoshifumi Mori
Assistant to Director, Research Center
Dr. Osamu Matsuda
Manager Opto-Electronics Research Dept., Device Technology Research Division
Dr. Masao Ikeda
Manager, Materials Research Division
Dr. Coe Ishimoto
Manager, New Areas, Materials Research Division

BACKGROUND

The Sony Group was reorganized in April 1995. The Group has sales of $37 billion. Sony's businesses are organized as Group companies and Division companies, both independent business units. Sales come approximately 75% from the Group companies (Consumer A&V Products Co., Components Co., and Recording Media & Energy Co.), and 25% from the Division companies (Broadcast Products Co., Business & Industrial Systems Co., Inforcom Products Co., Mobile Electronics Co., and Semiconductor Co.). Sony spends about 6% of sales on R&D or about $2.3 billion. Funding for research comes mainly from the business divisions, and some comes through the corporation. Overall, Sony has about 23,000 employees. The Research Center has 650.

Sony participates in government programs. The company had five people working for ten years on the MITI-funded Quantum Functional Device Program. While Sony saw MITI changing policy regarding patents, the company still believed programs would be funded over a sustained time period, that is, ten years.

Sony maintains good interactions with universities. It has an endowed chair at the University of Illinois. At any given time, it has about 1% of the Research Center staff at U.S. universities. Sony also provides sabbatical chairs for professors from abroad to visit for 3 to 12 months. The company provides living quarters and a small stipend for student interns, but pays the entire amount for professors. Annually, Sony spends 0.2 to 0.3% of its budget on this activity, which has increased in recent years.

Almost all staff hired in the Research Center are at the MS level. The company then has workers get PhDs, often based on their work at Sony. About 30% of the staff eventually receive their PhDs.

About 20% of the research is in the optoelectronics area; this percentage has been holding steady for the last few years. About 50 people work on lasers and 100 people work on optical disks, which is the company's main thrust. Sony is beginning to consider the display area. It sees itself being successful in peripherals rather than on the information highway itself, although the company is considering free space optical links.

The motivation for researchers to transfer to business units is that they are allowed to transfer their projects.

ORGANIZATION

The Research Center is divided into 4 Divisions (Materials Research, Device Technology Research, Systems & LSI Research, and Information and Communication System Research) and 4 Centers (Environmental Technology, Materials Analysis, Computational Science, and Technical Information). Several of the groups in the Research Center now report to one of the business divisions; that is, they span geography with organization. A new department for Card Systems Development was shown on the Research Center organization chart. Company representatives explained that when no business unit exists for a new product, they start an internal venture within the laboratory and grow it into a viable business. If a business unit does exist, then technology transfer is accomplished by moving people to that business unit.

TECHNOLOGY DISCUSSION

Red Lasers

Dr. Osamu Matsuda described the center's semiconductor laser device work. As indicated by his and other presentations, Sony has a good sense of history for its projects. It documents the milestone dates for projects and tracks its R&D expenses by project.

Since October 1994, Dr. Matsuda's group has been located in Yokohama, but it reports to the Device Technology Research Division in Tokyo. The eventual recipient for the devices is the semiconductor company in Atsugi headed by Dr. Watanabe (formerly head of the Research Center). Sony began work on semiconductor lasers in 1963. Its first commercial laser development was begun in 1977 by Dr. Y. Mori and was transferred to production seven years later. The final push from development to production took two years. Most recently, Dr. Masao Ikeda transferred the 680 nm laser to production in 1988. He started that work in 1982 and physically moved to the Atsugi facility for one-half year. In 1989, he returned and began the blue-green laser work. Dr. Matsuda spent 6.5 years in Atsugi carrying out development of optical devices. He said it was rare in Sony to return to research.

Dr. Matsuda showed a chart for the compact disk project indicating total R&D expenses were $4.7 million. Sony was producing 6 million CD lasers/month at that time. Company representatives believe Sony is the largest producer, and Rohm is its main competitor.

While the center has a rather sophisticated laser structure, it was doing nothing in telecommunications at the time of the JTEC visit. It has moved from a 9 mm to a 5.6 mm laser package to reduce cost. An Si-submount technology is incorporated in this.

Dr. Matsuda showed pictures of the center's totally automated laser assembly line. It is in a class-10,000 space, and it consists of six units that include a chip mounter, die bonder, wire bonder, cap sorter, and a test sorter. Sony has a corporate machine development group that builds internal prototypes and sells machines outside. It also works with internal groups to modify existing machines for special purposes. The machines developed have positioning accuracy of several tens of microns for the chip mounter and a few microns for ICs in their optical pickup heads.

Another successful project was the transfer of the center's high-power laser diode for magneto-optic storage use into production. These lasers have output power of 30 to 40 mW. The transfer from R&D into production took about 6 years and cost $4.7 million.

Sony representatives stated that they had no research on VCSELs.

Blue-Green Lasers

Dr. Ikeda discussed the Sony blue-green laser work. It began in 1986 - 1987 in ZnSe. In 1991 the center moved to ZnMgSSe for a cladding. Now the active layer is ZnCdSe (MQW). These layers are MBE grown on an n-GaAs substrate and buffer layer. Chlorine and nitrogen are used as dopants during the deposition. In 1993, center researchers demonstrated a green laser, and this year a blue laser. In the contact region, the ZnSe/ZnTe quantum well layers are "chirped" in thickness. This reduces the operating voltage to about 5 volts, but they believe they need to reduce this further by 1 to 1.5 volts. The threshold current is 45 mA. The physical performance is comparable to III-V devices, but reliability is the issue. The lifetimes are about 1 hr CW at 20 deg. C at the time of the JTEC visit. Stacking fault density is the problem. They believe these are coming from the GaAs-ZnSe:Cl interface and that they have a technique for removing them. They will transfer the process when they get several thousand hours CW. The center buys GaAs wafers outside. For deposition, the center has a two-chamber MBE machine: one chamber for III-Vs, the other for II-VIs.

The JTEC panelists were given a laboratory tour and shown both green and blue LEDs and lasers. The equipment was typical of any well-equipped optics laboratory.

DISCUSSION

The center representatives commented on GaInN work. Sony is watching this area, but center researchers think they are on the better material. They believe the broader spectrum observed in the LED will be a problem; that is, that the blue will not be pure enough. They are not sure this will carry over to the laser; however, they think the lifetime race will be won by ZnCdSe. They cited defect densities of 10 5 for ZnCdSe and 10 10 for GaInN.

Sony continues to do second harmonic generation (SHG) using KTP and LiNbO 3 in the Device Division. The application seems to be for the high powers needed for video disk storage. Recently Sony reported a 4th harmonic of YAG laser at 266 nm with a 1 watt output using 810 nm laser diodes as pump.

Sony's superresolution work is still in the Research Center.


Published: February 1996; WTEC Hyper-Librarian