Topics
半導體元件製程簡介
• Basic semiconductor devices • Basics of IC processing
Basic Devices
• • • • • Resistor Capacitor Diode Bipolar Transistor MOS Transistor
ρ
l
Resistor
h w
R=ρ
l wh
ρ: Resistivity
1
Resistor
• Resistors are made by doped silicon or polysilicon on an IC chip • Resistance is determined by length, line width, height, and dopant concentration
h d
κ
Capacitors
l
C =κ
hl d
κ: Dielectric Constant
Capacitors
• Charge storage device • Memory Devices, esp. DRAM • Challenge: reduce capacitor size while keeping the capacitance • High-κ dielectric materials
Capacitors
Dielectric Layer Dielectric Layer Poly Si Oxide Si Poly 2 Poly Si Poly 1 Heavily Doped Si Si
Parallel plate
Stacked
Deep Trench
2
Diode
• P-N Junction • Allows electric current go through only when it is positively biased.
Figure 3.14
Transition region
−− −− −− −− −− ++ ++ ++ ++ ++
P
N
Vn Vp V0
I-V Curve of Diode
Bipolar Transistor
• • • • • PNP or NPN Switch Amplifier Analog circuit Fast, high power device
I V -I 0
3
NPN and PNP Transistors
E B C
C
NPN Bipolar Transistor
C
Emitter Base Collector n+ Al•Cu•Si SiO2 n-epi Electron flow n+ buried layer P-substrate p+
B E
N P N p+ n+ p
E
B E
B
P N P
C
MOS Transistor
• Metal-oxide-semiconductor • Also called MOSFET (MOS Field Effect Transistor) • Simple, symmetric structure • Switch, good for digital, logic circuit • Most commonly used devices in the semiconductor industry
NMOS Device
Basic Structure
VG
VD
VG
“Metal” Gate
Ground
n+ Source p-Si n+ Drain
VD
4
NMOS Device
Positive charges VG = 0 VD Electron flow VG > V T > 0 VD > 0
PMOS Device
Negative charges VG = 0 VD Hole flow VG < V T < 0 VD > 0
“Metal” Gate SiO 2 n+ Source n+ Drain SiO 2 n+ Source +++++++ −−−−−−− p-Si n+ Drain SiO 2 p+ Source p+ Drain SiO 2 p+ Source
“Metal” Gate −−−−−−− +++++++ n-Si p+ Drain
p-Si
n-Si
No...