1. Field of the Invention
This invention relates to a semiconductor device which is constructed to a have high break-down voltage and to a method for manufacturing the device, and more particularly to a high voltage semiconductor device with an etched groove formed around a main junction by known etching technology, on which a grooved field plate and a grooved field limiting ring are utilized in order to increase the break-down voltage, and a method for manufacturing such semiconductor device.
2. Information Disclosure Statement
Generally, in order to make a high voltage semiconductor, many P-N junctions are arranged in parallel on a silicon substrate. When a high voltage is applied to such a structure in the reverse direction, there are problems which cause failure of the semiconductor device in normal operation since break-down occurs, very often, at the edge of a highly integrated chip.
In the prior art, attempts had been made to protect the semiconductor device against such failure. For example, one attempt at solving the problem formed a field limiting ring with diffusion material having the same type of impurity as that of the P+ diffusion region of the main junction at the edge of highly integrated chips.
However, this prior art method results in a design problem of the device because the number of field limiting rings must be increased at high voltage, resulting in problems manufacturing the integrated device.
A second approach had been proposed to eliminate the problem occurring in the prior art. This approach used as an anode electrode a field plate which was formed on an insulating layer to a desired length around the main junction of the device at the edge of highly integrated chips so that it is possible to make a large depletion of the main junction of the P+ type diffusion region and N- epitaxial layer. Due to this structure, the break-down voltage is increased, and failure in the device could be avoided.
However, there is a problem integrating the devices because of the extension of the field plate. Also, a further problem occurs when the length of field plate is over a certain length, since the break-down voltage does not increase further and the thickness of the insulating layer must be of a thickness that is difficult to obtain in the known semiconductor treatment process.
A third prior art device is formed by a combination of the first and second prior art devices. This device is constructed by a combination of the field plate and the field limiting ring around the main junction of the device in a highly integrated semiconductor device. Here the field plate is extended to a desired length from the main junction, and the field limiting ring is formed by a diffusing process with the material (the same material as the main junction) having the opposite type of semiconductor substrate. With this process, high break-down voltage semiconductor devices have been manufactured.
However, in the case of manufacturing a high break-down voltage semiconductor device using the combined structure of the field plate and the field limiting ring, a large amount of space is needed. Furthermore, problems occurred in designing the semiconductor device because of the plurality of field rings required, resulting in a high cost of the device.
Accordingly, it is an object of the present invention to provide a high voltage semiconductor device that provides a significant advancement over the prior art devices.
It is another object of the present invention to provide a semiconductor device having an improved high break-down voltage in a reverse direction and to provide a method for manufacturing such semiconductor devices.