United Microelectronics Corp.

Yao-Chin Cheng

Yu-Ming Lin

Shyh-Fann Ting

Cheng-Tung Huang

Jih-Wen Chou

Kuan-Cheng Su

Sheng-Hsing Yang

Meng-Yi Wu

Wen-Han Hung

Kun-Hsien Lee

Li-Shian Jeng

Shih-Jung Tu

Chih-Yuan Hsiao

Chung-Chiang Lin

A method of forming CMOS transistor is disclosed. A CMOS transistor having a first active area and a second active area is provided. In order to maintain the concentration of the dopants in the second active area, according to the method of the present invention an ion implantation process is performed to form a lightly doped drain (LDD) in the second active area after an epitaxial layer is formed in the first active area. On the other hand, the ion implantation process is performed to form the respective LDD of the first active area and the second active area. After the epitaxial layer in the first active area is formed, another ion implantation process is performed to implant dopants into the LDD of the second active area again.

Method of forming CMOS transistor

A method of reducing junction capacitance of a source/drain region. A gate oxide layer is formed on a first conductive type substrate. A polysilicon layer is formed and patterned on the gate. Light second conductive type ions are implanted into the substrate with the polysilicon layer as a mask. An insulation layer is formed to cover a side wall of the polysilicon layer. A first step heavy of ion implantation with second conductive type ions is perform to the substrate using the polysilicon layer and the spacer as mask, so that a heavily doped region is formed. A second step of heavy ion implantation with the second conductive type ions is performed to the substrate using the polysilicon layer and the spacer as masks, so that the heavily doped region is broadened and deepened with a smooth ion distribution profile.

Method of reducing junction capacitance of source/drain region

The present invention provides a method of forming a Metal Oxide Semiconductor (MOS) transistor on a substrate of a semiconductor wafer. A gate of the MOS transistor is formed on the substrate. A source and a drain of the MOS transistor are then formed in the substrate. An ion implantation process is performed to form a first doped region, a second doped region and a third doped region. The first doped region is positioned under the gate and overlaps with the channel of the MOS transistor. The second doped region is positioned in a predetermined portion of the substrate under the source. The third doped region is positioned in a predetermined portion of the substrate under the drain. The first doped region, the second doped region, the third doped region, the source, and the drain are all of the same type of semiconductor.

Method of forming a MOS transistor

A method of fabricating a transistor. A gate structure is formed on a substrate. A spacer is formed on a sidewall of the gate structure. A first doping step is performed with the gate structure and the spacer serving as masks to form a source/drain region in the substrate. A silicide layer is formed on the source/drain region. The spacer is removed. A second doping step is performed with the gate structure serving as a mask to form a lightly doped drain region in the substrate.

Method of fabricating a transistor

In one embodiment, the present invention is provided for higher BJT gain and more quality device. Providing a substrate incorporating a device, wherein the device is defined MOS region and BJT region. Conductivity-type well region is formed on the substrate, and then a gate oxide layer is formed on the conductivity-type well region of MOS region. Consequently, a polysilicon layer is deposited on the gate oxide layer of MOS region. Using photolithographic and etching process to define a gate, wherein the polysilicon layer is used as the gate of MOS region. Further implanting ions of a first conductive type into the substrate of MOS region. A first dielectric layer is forming on sidewall of the gate, wherein the first dielectric layer is used as a spacer of MOS region. Sequentially, a first photoresist layer is formed over substrate of BJT region to define an emitter of BJT. Then implanting second ions of the first conductive type into the substrate of MOS region to form source/drain regions by using said spacer as a mask. Simultaneously implanting second ions of the first conductive type into the substrate to form the emitter of BJT. Sequentially, a second photoresist layer is deposited over the device of the MOS region. Finally, implanting third ions of the first conductive type into the emitter of BJT inside the substrate.

Method of improving vertical BJT gain

Growing community of inventors

Hsinchu, Taiwan

Yao-Chin Cheng