Semiconductor device manufacturing: process – Coating with electrically or thermally conductive material – To form ohmic contact to semiconductive material
Reexamination Certificate
2000-06-21
2001-10-16
Nelms, David (Department: 2818)
Semiconductor device manufacturing: process
Coating with electrically or thermally conductive material
To form ohmic contact to semiconductive material
C438S930000
Reexamination Certificate
active
06303485
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method of producing a gallium nitride-based III-V Group compound semiconductor device.
BACKGROUND OF THE INVENTION
Compound semiconductor devices have been widely used in communication and for display. Due to recent requirement of blue light sources, gallium nitride-based III-V Group compound semiconductor devices have become the center of research and development. Gallium nitride-based III-V Group compound semiconductor devices generally comprise InGaN, GaAlN, and InAlGaN. The most efficient substrate used to grow gallium nitride-based III-V Group compound semiconductor devices is Al
2
O
3
single-crystal substrate. However, because the Al
2
O
3
substrate can not conduct electricity, in producing a device such as a light-emitting diode (LED), its p-contact and n-contact must be fabricated on the same surface and connected to the p-type layer and the n-type layer of the LED via an ohmic contact layer, respectively. The contact is generally made of metallic material of a very thin thickness to prevent from shielding light. Therefore, the electronic characteristic of the ohmic contact layer has an enormous influence on the efficiency of the LED. Moreover, the hole mobility of the p-type layer of gallium nitride-based III-V Group compound semiconductor device is low, resulting in a high impedance of the p-type layer. Therefore, the diffusion of the hole current becomes an issue in the production of this device.
In U.S. Pat. No. 5,563,422, the Nichia company of Japan discloses a method of producing a gallium nitride-based III-V Group compound semiconductor device, wherein a metal film is electroplated on the p-type layer and the diffusion of the hole current is increased by annealing. Because hydrogen atoms bonded with the acceptors will be driven out during the annealing process, the acceptor impurities can be activated so as to improve the electronic characteristic of the ohmic contact layer. However, for metals such as nickel, chromium, aluminum, and gold on the p-type layer of gallium nitride, the efficiency and impedance of the ohmic contact can not be effectively improved.
SUMMARY AND OBJECTS OF THE PRESENT INVENTION
Accordingly, the primary object of the present invention is to provide a method of fabricating a p-contact of a gallium nitride-based III-V Group compound semiconductor device. The proposed method can improve the electronic characteristic of the ohmic contact layer thereof.
To achieve the object, the present invention discloses a method of producing a gallium nitride-based III-V Group compound semiconductor device, wherein beryllium ions are diffused into the p-type layer of gallium nitride so as to increase hole mobility. Contacts are then added in the subsequent fabrication process, thereby forming contacts having low-impedance ohmic contact layers.
The various objects and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawings, in which:
REFERENCES:
patent: 5563422 (1996-10-01), Nakamura et al.
patent: 6093965 (2000-07-01), Nakamura et al.
Liu Weng Ming
Sung Ying Che
Arima Optoelectronics Corp.
Nelms David
Nhu David
Rosenberg , Klein & Lee
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