basic bipolar process description bipolar process flow –vertical npn –lateral pnp –jfet...
TRANSCRIPT
Basic Bipolar Process Description
• Bipolar Process Flow– Vertical npn– Lateral pnp– JFET
– Prepared by Randy Geiger, September 2001
Bipolar Process Flow
P-substrate
n+ buried collector implant
n-epitaxy
Buried collector
Isolation Diffusionp-base diffusion n+ emitter diffusionOxidationContact OpeningsMetalization Bipolar Process Flow
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 6055 7065 751
5
10
20
15
30
25
40
35
50
45
55
3 2
14
47
14
46
12
22
NOT TOSCALE
Note: 24 requiredBetween p-base and isolation diffusion
1 5 10 15 20 25 30 35 40 45 50 6055 7065 751
5
10
20
15
30
25
40
35
50
45
55
3 2
14
63
6
12
2
2
Note: 24 requiredBetween p-base and isolation diffusion
Note: Not to vertical Scale
58
1 5 10 15 20 25 30 35 40 45 50 6055 7065 751
5
10
20
15
30
25
40
35
50
45
55
3 2
14
63
6
12
2
2
Note: 24 requiredBetween p-base and isolation diffusion
Note: Not to vertical Scale
58
1 5 10 15 20 25 30 35 40 45 50 6055 7065 751
5
10
20
15
30
25
40
35
50
45
55
63
Note: Not to vertical Scale
58
67
62
1 5 10 15 20 25 30 35 40 45 50 6055 7065 751
5
10
20
15
30
25
40
35
50
45
55
Note: Not to vertical Scale
67
62
Bounding Area = 41542
1 5 10 15 20 25 30 35 40 45 50 6055 7065 751
5
10
20
15
30
25
40
35
50
45
55
16
13
Bounding Area = 208
Comparison with Area for n-channel MOSFET in Bulk CMOS
1 5 10 15 20 25 30 35 40 45 50 6055 7065 751
5
10
20
15
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25
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45
55
14
12
Bounding Area = 168
Active Area = 62
Minimum-Sized MOSFET
1 5 10 15 20 25 30 35 40 45 50 6055 7065 751
5
10
20
15
30
25
40
35
50
45
55
Note: Not to vertical Scale
67
62
MOSFET BJT
Area Comparison between BJT and MOSFET
• BJT Area = 4154 2
• n-channel MOSFET Area = 168 2
• Area Ratio 25:1