Basic Bipolar Process Description Bipolar Process Flow Vertical

Basic Bipolar Process Description • Bipolar Process Flow – Vertical npn – Lateral pnp – JFET – Prepared by Randy Geiger, September 2001

Bipolar Process Flow Metalization Bipolar Process Flow Contact Openings Oxidation Isolation p-base n+Diffusion emitter diffusion n-epitaxy n+ buried collector implant Buried collector P-substrate

Base Emitter n+ buried collector implant Buried collector Vertical npn BJT Collector

Lateral pnp Modification B E E Lateral pnp BJT C CB

JFET Modification S B E D C G

BJT Layout and Area Issues • BJT Layout • BJT Area Requirements • Comparison of Area between MOS and Bipolar Processes

1 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75

1 1 5 10 15 20 25 30 35 40 45 5 10 15 20 25 30 3 l 35 40 45 50 55 60 65 70 75

1 1 5 10 15 20 25 30 35 40 45 50 5 10 15 20 25 30 3 l 35 40 45 50 55 2 l 55 60 65 70 75

1 1 5 10 15 20 25 30 35 40 45 50 5 10 15 20 15 l 25 30 3 l 35 40 45 50 55 2 l 55 60 65 70 75

1 1 5 10 15 20 25 30 35 40 45 50 5 10 15 20 19 l 25 2 l 30 3 l 35 40 45 50 55 2 l 55 60 65 70 75

1 1 5 10 15 20 25 30 35 40 45 50 55 5 43 l 10 15 20 25 19 l 14 l 30 3 l 35 40 45 50 55 2 l 60 65 70 75

1 1 5 10 15 20 25 30 35 40 45 50 55 5 43 l 10 15 20 25 30 19 l 14 l 14 l 3 l 35 40 45 50 55 2 l 60 65 70 75

1 1 5 10 15 20 25 30 35 40 45 50 55 60 47 l 5 10 15 20 25 19 l 14 l 30 3 l 35 40 45 50 55 2 l 65 70 75

1 1 5 10 15 20 25 30 35 40 45 50 55 60 47 l 5 10 15 20 19 l 14 l 25 14 l 30 4 l 35 40 45 50 55 3 l 2 l 65 70 75

1 1 5 10 15 20 25 30 35 40 45 50 55 60 47 l 5 10 15 20 14 l 25 12 l 14 l 2 l 2 l 30 4 l 35 40 45 50 55 NOT TO SCALE 6 l 3 l 2 l Note: 24 l required Between p-base and isolation diffusion 65 70 75

1 1 5 10 15 20 25 30 35 40 45 50 55 60 65 63 l 5 10 Note: Not to vertical Scale 15 20 12 l 25 58 l 14 l 2 l 30 2 l 6 l 3 l 2 l 35 40 45 50 55 Note: 24 l required Between p-base and isolation diffusion 70 75

1 1 5 10 15 20 25 30 35 40 45 50 55 60 65 63 l 5 10 Note: Not to vertical Scale 15 20 12 l 25 58 l 14 l 2 l 30 2 l 6 l 3 l 2 l 35 40 45 50 55 Note: 24 l required Between p-base and isolation diffusion 70 75

1 1 5 10 15 20 25 30 35 40 45 50 55 60 65 63 l 5 10 15 67 l 20 62 l 25 58 l 30 35 40 45 50 55 Note: Not to vertical Scale 70 75

1 1 5 10 15 20 25 30 35 40 45 50 55 60 65 5 10 15 67 l 20 62 l 25 30 35 40 45 50 55 Bounding Area = 4154 l 2 Note: Not to vertical Scale 70 75

1 1 5 10 15 20 25 30 35 40 45 50 55 5 10 15 Comparison with Area for n-channel MOSFET in Bulk CMOS 20 16 l 25 30 13 l 35 40 45 50 55 Bounding Area = 208 l 2 60 65 70 75

1 1 5 10 15 20 25 30 35 40 45 50 55 5 10 Minimum-Sized MOSFET 15 20 14 l 25 30 12 l 35 40 45 50 55 Bounding Area = 168 l 2 Active Area = 6 l 2 60 65 70 75

1 1 5 10 15 20 25 30 35 40 45 50 55 60 65 5 10 15 67 l 20 62 l 25 30 35 40 45 MOSFET BJT 50 55 Note: Not to vertical Scale 70 75

Area Comparison between BJT and MOSFET • BJT Area = 4154 l 2 • n-channel MOSFET Area = 168 l 2 • Area Ratio 25: 1

That’s all folks!