Radio frequency horizontal double-diffusion-field effect transistor and manufacturing method thereof

Abstract

The invention discloses a radio frequency horizontal double-diffusion-field effect transistor comprising a polysilicon gate and a faraday shielding layer which is a polysilicon faraday shielding layer. The radio frequency horizontal double-diffusion-field effect transistor adopts a polysilicon faraday shielding layer structure. Compared with a traditional preparation technology of a faraday shielding payer, the preparation technology of the polysilicon faraday shielding layer is simple, a thermal oxidation process is added once, and an oxide layer deposition and metal deposition and corrosion process below the faraday shielding layer is reduced once. Quality of an oxide layer, prepared by the method, below the faraday shielding layer grows better than quality of a normal faraday shielding layer which grows through a deposition way, and therefore durability of a component is enhanced. Compared with a component of the normal faraday shielding layer, the component of the radio frequency horizontal double-diffusion-field effect transistor has the advantages of being same in breakdown voltage and on-resistance and the like. A step gate structure prepared by the method can also play a role in preventing infusion (host controller interface (HCI)) of hot carriers.

Description

technical field [0001] The invention relates to a semiconductor integrated circuit, in particular to a radio frequency lateral double-diffusion field effect transistor, and also relates to a manufacturing method of the transistor. Background technique [0002] With the advent of the 3G era, more and more communication fields require the development of more powerful radio frequency (RF) devices. Radio Frequency Lateral Double Diffused Field Effect Transistor (RFLDMOS), due to its very high output power, has been widely used in portable wireless base station power amplification as early as the 1990s, and its application frequency is 900MHz-3.8GHz. Compared with traditional silicon-based bipolar transistors, RFLDMOS has better linearity, higher power and gain. Today, RFLDMOS is more popular than bipolar, and GaAs devices. [0003] The current structure of RFLDMOS is as follows figure 1 As shown, a substrate doped with a high-concentration P-type impurity, that is, a P-type s...

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Problems solved by technology

[0004] At present, under normal circumstances, the oxide layer under the Faraday shielding layer prepared by this method is grown by

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