Numéro
J. Phys. IV France
Volume 06, Numéro C3, Avril 1996
WOLTE 2
Proceedings of the Second European Workshop on Low Temperature Electronics
Page(s) C3-113 - C3-118
DOI https://doi.org/10.1051/jp4:1996317
WOLTE 2
Proceedings of the Second European Workshop on Low Temperature Electronics

J. Phys. IV France 06 (1996) C3-113-C3-118

DOI: 10.1051/jp4:1996317

The Impact of Ge Grading on the Bias and Temperature Characteristics of SiGe HBT Precision Voltage References

M.S. Latham, J.D. Cressler, A.J. Joseph and R.C. Jaeger

Alabama Microelectronics Science and Technology Center, Electrical Engineering Department, 200 Broun Hall, Auburn University, Auburn, Alabama 36849, U.S.A.


Abstract
We analyze the effects that the Ge profile shape has upon the bias and temperature characteristics of SiGe HBT's. The widely used bandgap reference (BGR) design equation and a more general analytical expression we developed incorporating Ge grading are used to compare silicon devices to their SiGe counterparts. Measurement and simulation show that although the Ge-ramp effect is negligible in the -55 to 85 °C range, it can become important as the temperature drops, perhaps affecting the operation of SiGe circuits in the 77 K regime.



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