TECHNICAL SEMINAR CO-ORDINATOR Mr. SOMASHEKHAR G.C (PhD) (Asst . Professor ,Dept. of ECE ,RGIT) UNDER THE GUIDANCE OF Prof. K.V BALACHANDRA (HOD of ECE, RGIT)
1. Introduction2. Abstract3. Characteristics of CMOS Technology4. Characteristics of Bipolar Technology5. Combine advantages in BiCMOS Technology6. BiCMOS Fabrication7. BiCMOS Integrated Circuits
8. Advantages of BiCMOS9. Disadvantages of BiCMOS10. Applications of BiCMOS11. Comparison between CMOS and BiCMOS12. BiCMOS Products13. Conclusion14. Literature Survey
The history of semiconductor devices started in 1930’s when Lienfed and Heil first proposed the mosfet. Bipolar Technology was started in 1980’s. CMOS Technology was also started in mid 1980’s. Later in 1990 there was a cross over between bipolar and CMOS Technology. In BiCMOS technology, both the MOS and bipolar device are fabricated on the same chip .
The objective of the BiCMOS is to combine bipolar and CMOS so as to exploit the advantages of both the technlogies. Today BiCMOS has become one of the dominant technologies used for high speed, low power and highly functional VLSI circuits. The process step required for both CMOS and bipolar are similar so the BiCMOS process has been enhanced and integrated into the CMOS process without any additional steps.
The primary approach to realize high performance BiCMOS devices is the addition of bipolar process steps to a baseline CMOS process. The BiCMOS gates could be used as an effective way of speeding up the VLSI circuits. The applications of BiCMOS are vast. Advantages of bipolar and CMOS circuits can be retained in BiCMOS chips. BiCMOS technology enables high performance integrated circuits IC’s but increases process complexity.
BiCMOS technology is a combination of Bipolar and CMOS technology. CMOS technology offers less power dissipation, smaller noise margins, and higher packing density. Bipolar technology, on the other hand, ensures high switching and I/O speed and good noise performance Now we are in 3rd Generation BiCMOS Technology.
BiCMOS technology accomplishes both - improved speed over CMOS and lower power dissipation than bipolar technology. The main drawback of BiCMOS technology is the higher costs due to the added process complexity. This greater process complexity in BiCMOS results in a cost increase compared to conventional CMOS technology.
Lower static power dissipation Higher noise margins Higher packing density High yield with large integrated complex functions High input impedance (low drive current) Scaleable threshold voltage High delay load sensitivity Low output drive current (issue when driving large capacitive loads) Low transconductance, where transconductance, gm Vin Bi-directional capability (drain & source are interchangeable) A near ideal switching device Low gain
Higher switching speed Higher current drive per unit area, higher gain Generally better noise performance and better high frequency characteristics Improved I/O speed (particularly significant with the growing importance of package limitations in high speed systems). high power dissipation lower input impedance (high drive current) low packing density low delay sensitivity to load High transconductance gm (gm Vin) It is essentially unidirectional.
It follows that BiCMOS technology goes some way towards combining the virtues of both CMOS and Bipolar technologies Improved speed over purely-CMOS technology Lower power dissipation than purely-bipolar technology(Lower power consumption than bipolar) Flexible I/Os for high performance Improved current drive over CMOS Improved packing density over bipolar High input impedance Low output impedance High Gain and low noise
ADVANTAGES Improved speed over CMOS Improved current drive over CMOS Improved packing density over bipolar Lower power consumption than bipolar High input impedance Low output impedance High Gain and low noise
DISADVANTAGES Increased manufacturing process complexity higher cost Speed degradation due to scaling longer fabrication cycle timeBiCMOS process Bipolar process + Well + Gate Oxide & Poly + CMOS process
LITERATURE SURVEY BOOKS:VLSI Basic Design by Douglas A. Pucknell and Kamran Eshraghian WEBSITES:http://www.vlsihandbook.comhttp://www.bicmosdesign.comhttp://website.informer.comhttp://www.freepatentsonline.com/6927460.html