United Microelectronics Corp.

Cheng-Choug Hung

Hua-Chou Tseng

Cheng-Wen Fan

Chun-Yi Lin

Chia-Hong Chin

A method for forming a SiGe HBT, which combines a SEG and Non-SEG growth, is disclosed. The SiGe base layer is deposited by a Non-SEG method. Then, the first-emitter layer is developed directly upon the SiGe base layer that has a good interface quality between the base-emitter. Next, a second poly silicon layer, which has a dopant concentration range within 1E19 to 1E21 (atom/cc), is deposited by SEG method. It not only reduces the resistance of the SiGe base layer, but also avoids the annealing that may influence the performance of the device.

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Changhua, Taiwan

Cheng-Choug Hung