Improved Lateral PNP With Polysilicon Contacts
Original Publication Date: 1986-Jun-01
Included in the Prior Art Database: 2005-Mar-09
A method has been proposed to improve the lateral PNP (LPNP) in semiconductor devices by forming small PNP emitters by image transfer from a sidewall. The narrow width of the smaller emitter and self-aligned contact reduces series emitter resistance. Beta characteristics also are significantly improved. The invention calls for changes in a conventional bipolar manufacturing process following a 450 L/square resistor implant step as follows: a. Blanket LPCVD (low pressure chemical vapor deposition) nitride 800ŒC, 100 nm thick. b. Photoresist (PR), 2 m thick, patterned with LPNP mask #1. Plasma harden the resist. c. Blanket plasma oxide, 0.6 m thick, 245ŒC. d. Blanket RIE (reactive ion etch) plasma oxide, 0.6 m, end point detect on the underlying nitride layer and overetch slightly.