High-voltage transistor and manufacturing method thereof

Abstract

The invention discloses a high-voltage transistor and a manufacturing method thereof. The high-voltage transistor is formed by a first oxidizing layer between a drain terminal and a grid electrode and a second oxidizing layer used as a grid oxidizing layer in different steps. The first oxidizing layer and the second oxidizing layer can have different thicknesses, then the thickness of the second oxidizing layer can be maintained without influencing the saturation current when he thickness of the first oxidizing layer is increased so as to enhance a breakdown voltage, and then the breakdown voltage is enhanced on the premise of not influencing the saturation current. In addition, the manufacturing method of the high voltage transistor is compatible with traditional manufacturing process of the high-voltage transistor, and does not need additional mask.

Description

technical field [0001] The invention relates to the technical field of silicon semiconductor devices, in particular to a high-voltage transistor and a manufacturing method thereof. Background technique [0002] At present, the application of high-voltage devices in integrated circuit products is becoming more and more extensive, and their influence and attention are getting higher and higher. The normal operating voltage of high-voltage devices is greater than 8V, and the normal operating voltage of ordinary low-voltage devices is not greater than 5V. There are many kinds of high-voltage devices, and the structure of a common high-voltage transistor is as follows figure 1 shown. figure 1 Among them, the high-voltage transistor includes a high-voltage well region 11; a source drift region 121 and a drain drift region 122 are both formed in the high-voltage well region 11; an oxide layer 13 is formed on the high-voltage well region 11; a gate 14 , formed on the oxide layer ...

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Problems solved by technology

However, in such figure 1 In the structure of the high-voltage transistor shown, since the oxide layer 13 is not only an oxide layer between the drain terminal and the gate 14, but also a gate oxide layer at the same time, the thickness of the oxide layer between the drain terminal and the gate 14 is increased, It will inevitably lead to an increase in the thickness of the gate oxide layer at the same time, which is not conducive to the formation of a conductive channel, thereby reducing the saturation current

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