Coherent light generators – Particular active media – Semiconductor
Reexamination Certificate
1998-01-30
2001-02-06
Anderson, Bruce C (Department: 2874)
Coherent light generators
Particular active media
Semiconductor
C372S038060
Reexamination Certificate
active
06185240
ABSTRACT:
FIELD OF THE INVENTION
The present invention pertains, in general, to lasers and, more particularly, to vertical cavity surface emitting lasers.
BACKGROUND OF THE INVENTION
Recently, there has been an increased interest in a new type of laser device called a vertical cavity surface emitting laser (VCSEL). Several advantages of VCSEL devices are apparent, such as having a circular beam, two-dimensional array capability, and allowing wafer scale testing. These advantages are due in part from advances in metal organic vapor phase epitaxy (MOVPE) and molecular beam epitaxy (MBE) that allow monolithic growth of diffractive Bragg reflectors (DBRs) for VCSELs.
However, even with these advantages, VCSEL devices are more susceptible to electro-static discharge (ESD) events because of smaller active volume. Electro-static discharge events are events where a high static charge is built up and subsequently discharged. When the high static charge discharges through a VCSEL, it will be catastrophically damaged. Thus, conventional VCSEL's are limited to applications that are not susceptible to ESD events, which reduces the number of possible applications for VCSEL's.
Thus it is highly desirable and an object of the present invention to provide a protective circuitry to increase the VCSEL ESD damage threshold.
It is another purpose of the present invention to provide for a method to integrate the protective diode with the VCSELs.
SUMMARY OF THE INVENTION
The above problems and others are at least partially solved and the above objects are realized in a semiconductor laser having electro-static discharge (ESD) protection. To provide the ESD protection, a vertical cavity surface emitting laser (VCSEL) is fabricated and a diode is fabricated and connected in parallel reverse orientation to the VCSEL. When a reverse biased ESD event is applied to the VCSEL, the parallel connected diode will provide a very low resistance path to quickly drain off the charge before it can damage the VCSEL. Since the reverse biased ESD damage threshold is typically lower than the forward biased ESD damage threshold, the proposed solution will increase the VCSEL ESD tolerence level to the forward biased ESD damage threshold level. The parallel connected diode is fabricated adjacent and in the same fabrication steps in which the VCSEL is formed. Thus, very little extra chip real estate is required and no extra fabrication steps are required to provide the protection.
REFERENCES:
patent: H322 (1987-08-01), Simons
patent: 4924473 (1990-05-01), Burgyan et al.
patent: 5468656 (1995-11-01), Shieh et al.
patent: 5493577 (1996-02-01), Choquette et al.
patent: 5541443 (1996-07-01), Lee et al.
patent: 5550852 (1996-08-01), Patel et al.
patent: 5577064 (1996-11-01), Swirhun et al.
patent: 5610931 (1997-03-01), Huang
patent: 5990499 (1999-11-01), Kuhlmann et al.
patent: 62-45193 (1987-02-01), None
patent: 62-69694 (1987-03-01), None
patent: 63-177494 (1988-07-01), None
patent: 2-246360 (1990-10-01), None
patent: 9-27657 (1997-01-01), None
patent: WO 97/37390 (1997-10-01), None
Claisse Paul R.
Jiang Wenbin
Kiely Philip A.
Anderson Bruce C
Koch William E.
Leung Quyen
Motorola Inc.
Parsons Eugene A.
LandOfFree
Semiconductor laser having electro-static discharge protection does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Semiconductor laser having electro-static discharge protection, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Semiconductor laser having electro-static discharge protection will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2575500