University of California, Berkeley
College of Engineering
Department of Electrical Engineering and Computer Sciences
EECS 130
Integrate Circuit Devices
Midterm Exam #2 Part one
(35% of total point weighting)
March 14, 1996
Two Problems. One 8 ½ “ x 11 “ sheet allowed for formula reference.
1. In a forward biased pn junction diode, Ln, p << device length.
(a) Write down the expression for stored charge on both sides of the pn
junction, Qn and Qp, in terms of device parameters such as ND, NA,
VA,…etc. (3 points)
(b) Rewrite the expression of current density in terms of Qn and Qp. (3 points)
(c) Interpret the physical meaning of the expression you derived in part (b). (2
points)
(d) How does the current change (increase or decrease) at a given forward
bias as temperature increase? Demonstrate your answer with equations
(use the back of this sheet if necessary). (4 points)
