這是小弟看了一本半導體物理書
有五個問題不太能解出來
希望有高手能幫小弟指點迷津
1. A one-side step junction (p+n) is built in silicon
that has an avalance voltage of 500 V and Nd = 4.5 x10^14 /cm^3,
(a) if it is a“plane”junction what is
the small signal capacitance/area just before breakdown?
(b)if it is a “planar”junction, with a junction depth 1.0μm,
what is the small signal capacitance/area just before breakdown?
2. Given a one-side n+p silicon with the following:
A=10^-3 cm2
Na=1.0×1016/cm3
Width of neutral p material = 5.0 μm
Excess carrier lifetime throughout = 1.0 × 10^-6/sec
T=27度C
Calculate the total current under a 10-volts reverse bias.
3. Given the silicon pn junction diode with:
p-type:Na = 10^16/cm^3
μn= 1250 cm^2/V．S
Dn=32.5 cm^2/S
Ln=56.8 μm
WE=10μm
Short base
n-type:Nd=10^16/cm^3
μp=400 cm^2/V．S
Dp=10.5 cm^2/S
Lp =10.2 μm
WB = 100μm
Long base
Calculate the amount of minority carrier charge in the neutral n-type side
when the above diode is forward biased
so that ideal diode current of 5 mA flows.
4. Given an n-pn prototype bipolar junction transistor
with the following structure:
Neutral emitter width = 2.0μm
Neutral base width = 0.5μm
Minority carrier lifetime in all portions of the device = 1.0μsec
Base doping = 1.0×10^17/cm^3
μnB =800cm^2/V．S
Collector doping 1.0x10^15/cm^3
Cross section area = 10^-3 cm^2
BF = 100
Base transport factor =0.995
Calculate the emitter doping. Neglect any space charge region currents.
5. The accumulation and the high frequency invertion capacitances
for an MOS capacitor with p-type silicon are 10 pF and 3 pF , respectively .
Capacitance Area =10^-4 cm^-2.
Aluminum Metal with ΦM = 4.1eV.
(a) Find the oxide thickness, tox(from the accumulation capacitance)
(b) Find the maximum depletion depth
(from the high frequency inversion capacitance).
For (c) through (g) only,assume NA = 1.5 x10^16 cm^-3.
(c) Find ψp
(d) Find the work function of the silicon.
(e) Find the ideal flat band voltage assuming on oxide charge is present.
(f) The measured VFB = -2.5V.
Assume all of the oxide charge is fixed at the interface and
find the surface charge density.
(g) What is the sign(＋/－)of the charge calculated in (f) How do you know?
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※ Origin: 摩卡小築 <moca.csie.chu.edu.tw>
◆ From: 163.23.217.204