Chinese Academy of Sciences

Chao Xia

Yuehui Yu

Xinhong Cheng

Dawei Xu

Zhongjian Wang

Dawei He

Zhaorui Song

The present invention relates to a manufacturing method of SOI devices, and in particular, to a manufacturing method of SOI high-voltage power devices. The method comprises steps of: forming a first oxide layer in a section on the surface of the SOI substrate; removing the first oxide layer to form a depressed area in the corresponding section of the upper surface of the SOI substrate; forming a second oxide layer, the upper surface of which is as high as the that of the SOI substrate, in the depressed area formed in step (B); performing photoetching and doping processes to form a P-type region, an N-type region and a gate region on the thus-formed structure where the second oxide layer is formed; forming a third oxide layer by deposition on the drift region of the structure after P-type and N-type regions are formed; wherein the total thickness of the third oxide layer and the second oxide layer approximates to the thickness of the buried oxide layer in the SOI substrate; and forming metal sub-regions, which are respectively in contact with the P-type region, the N-type region and the gate region, on the structure where the third oxide layer is formed, thereby forming a high-voltage power device.

Manufacturing method of SOI high-voltage power device

A method of manufacturing a SOI high voltage power chip with trenches is disclosed. The method comprises: forming a cave and trenches at a SOI substrate; filling oxide in the cave; oxidizing the trenches, forming oxide isolation regions for separating low voltage devices at the same time; filling oxide in the oxidized trenches; and then forming drain regions, source regions and gate regions for a high voltage power device and low voltage devices. The process involves depositing an oxide layer overlapping the cave of the SOI substrate. A SOI high voltage power chip thus made will withstand at least above 700V voltage.

Method for fabricating SOI high voltage power chip with trenches

The present invention relates to a method of fabricating an SOI SJ LDMOS structure that can completely eliminate the substrate-assisted depletion effects, comprising the following steps: step one: a conducting layer is prepared below the SOI BOX layer using the bonding technique; the conducting layer is prepared in the following way: depositing a barrier layer on a first bulk silicon wafer, and then depositing a charge conducting layer, thereby obtaining a first intermediate structure; forming a silicon dioxide layer on a second bulk silicon wafer via thermal oxidation, then depositing a barrier layer, and finally depositing a charge conducting layer, thereby obtaining a second intermediate structure; bonding the first intermediate structure and the second intermediate structure using the metal bonding technology to arrange the conducting layer below the SOI BOX layer; step two: a SJ LDMOS structure is fabricated on the SOI substrate having a conducting layer. The present invention is capable of releasing the charge accumulated at the lower interface of the BOX layer, eliminating the effect of the vertical charge on the charge balance between the p-type pillar and the n-type pillar, and therefore completely eliminating the substrate-assisted depletion effects and elevating the breakdown voltage of the device.

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Shanghai, China

Chao Xia