📄 ch02.1.htm
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<SUB CLASS="SubscriptVariable">
GS</SUB>
– V<SUB CLASS="Subscript">
t</SUB>
<SUB CLASS="SubscriptVariable">
n</SUB>
) ; <SPAN CLASS="EquationVariables">
V</SPAN>
<SUB CLASS="SubscriptVariable">
DS</SUB>
> <SPAN CLASS="EquationVariables">
V</SPAN>
<SUB CLASS="SubscriptVariable">
DS</SUB>
<SUB CLASS="Subscript">
(sat)</SUB>
(velocity saturated).</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnNumber">
<A NAME="pgfId=378531">
</A>
(2.16)</P>
</TD>
</TR>
</TABLE>
<P CLASS="Body">
<A NAME="pgfId=204553">
</A>
We can see this behavior for the short-channel transistor characteristics in Figure 2.4(a) and (c). </P>
<P CLASS="Body">
<A NAME="pgfId=205584">
</A>
Transistor current is often specified per micron of gate width because of the form of Eq. 2.16. As an example, suppose <SPAN CLASS="EquationVariables">
I</SPAN>
<SUB CLASS="SubscriptVariable">
DSn</SUB>
<SUB CLASS="Subscript">
(sat)</SUB>
/ <SPAN CLASS="EquationNumber">
W</SPAN>
= 300 <SPAN CLASS="Symbol">
m</SPAN>
A<SPAN CLASS="Symbol">
m</SPAN>
m<SUP CLASS="Superscript">
–1</SUP>
for the <SPAN CLASS="EmphasisPrefix">
n</SPAN>
-channel transistors in our G5 process (with <SPAN CLASS="EquationVariables">
V</SPAN>
<SUB CLASS="SubscriptVariable">
DS</SUB>
= 3.0 V, <SPAN CLASS="EquationVariables">
V</SPAN>
<SUB CLASS="SubscriptVariable">
GS</SUB>
= 3.0 V, <SPAN CLASS="EquationNumber">
V</SPAN>
<SUB CLASS="Subscript">
t</SUB>
<SUB CLASS="SubscriptVariable">
n</SUB>
= 0.65 V, <SPAN CLASS="EquationNumber">
L</SPAN>
<SUB CLASS="Subscript">
eff</SUB>
= 0.5 <SPAN CLASS="Symbol">
m</SPAN>
m and <SPAN CLASS="EquationNumber">
T</SPAN>
<SUB CLASS="Subscript">
ox</SUB>
= 100 Å). Then <SPAN CLASS="EquationVariables">
E</SPAN>
<SUB CLASS="SubscriptVariable">
x</SUB>
<SPAN CLASS="Symbol">
ª</SPAN>
(3 – 0.65) V / 0.5 <SPAN CLASS="Symbol">
m</SPAN>
m <SPAN CLASS="Symbol">
ª</SPAN>
5 V<SPAN CLASS="Symbol">
m</SPAN>
m<SUP CLASS="Superscript">
–1</SUP>
, </P>
<TABLE>
<TR>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnRight">
<A NAME="pgfId=378555">
</A>
</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnCenter">
<A NAME="pgfId=378557">
</A>
</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnCenter">
<A NAME="pgfId=378559">
</A>
<SPAN CLASS="EquationVariables">
I</SPAN>
<SUB CLASS="SubscriptVariable">
DSn</SUB>
<SUB CLASS="Subscript">
(sat)</SUB>
/W</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnLeft">
<A NAME="pgfId=378561">
</A>
</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqn">
<A NAME="pgfId=378563">
</A>
</P>
</TD>
</TR>
<TR>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnRight">
<A NAME="pgfId=378565">
</A>
v<SUB CLASS="Subscript">
max</SUB>
<SUB CLASS="SubscriptVariable">
n</SUB>
</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnCenter">
<A NAME="pgfId=378567">
</A>
=</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnCenter">
<A NAME="pgfId=378569">
</A>
–––––––––––––––</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnLeft">
<A NAME="pgfId=378571">
</A>
</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnNumber">
<A NAME="pgfId=378573">
</A>
(2.17)</P>
</TD>
</TR>
<TR>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnRight">
<A NAME="pgfId=378575">
</A>
</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnCenter">
<A NAME="pgfId=378577">
</A>
</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnCenter">
<A NAME="pgfId=378579">
</A>
C<SUB CLASS="Subscript">
ox</SUB>
(<SPAN CLASS="EquationVariables">
V</SPAN>
<SUB CLASS="SubscriptVariable">
GS</SUB>
– V<SUB CLASS="Subscript">
t</SUB>
<SUB CLASS="SubscriptVariable">
n</SUB>
)</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnLeft">
<A NAME="pgfId=378581">
</A>
</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqn">
<A NAME="pgfId=378583">
</A>
</P>
</TD>
</TR>
<TR>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnRight">
<A NAME="pgfId=378585">
</A>
</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnCenter">
<A NAME="pgfId=378587">
</A>
</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnCenter">
<A NAME="pgfId=378589">
</A>
</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnLeft">
<A NAME="pgfId=378591">
</A>
</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqn">
<A NAME="pgfId=378593">
</A>
</P>
</TD>
</TR>
<TR>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnRight">
<A NAME="pgfId=378595">
</A>
</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnCenter">
<A NAME="pgfId=378597">
</A>
</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnCenter">
<A NAME="pgfId=378599">
</A>
(300 <SPAN CLASS="Symbol">
¥</SPAN>
10<SUP CLASS="Superscript">
–6</SUP>
) (1 <SPAN CLASS="Symbol">
¥</SPAN>
10<SUP CLASS="Superscript">
6</SUP>
)</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnLeft">
<A NAME="pgfId=378601">
</A>
</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqn">
<A NAME="pgfId=378603">
</A>
</P>
</TD>
</TR>
<TR>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnRight">
<A NAME="pgfId=378605">
</A>
</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnCenter">
<A NAME="pgfId=378607">
</A>
=</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnCenter">
<A NAME="pgfId=378609">
</A>
––––––––––––––––––</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnLeft">
<A NAME="pgfId=378611">
</A>
</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqn">
<A NAME="pgfId=378613">
</A>
</P>
</TD>
</TR>
<TR>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnRight">
<A NAME="pgfId=378615">
</A>
</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnCenter">
<A NAME="pgfId=378617">
</A>
</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnCenter">
<A NAME="pgfId=378619">
</A>
(3.45 <SPAN CLASS="Symbol">
¥</SPAN>
10<SUP CLASS="Superscript">
–3</SUP>
) (3 – 0.65)</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnLeft">
<A NAME="pgfId=378621">
</A>
</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqn">
<A NAME="pgfId=378623">
</A>
</P>
</TD>
</TR>
<TR>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnRight">
<A NAME="pgfId=378625">
</A>
</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnCenter">
<A NAME="pgfId=378627">
</A>
</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnCenter">
<A NAME="pgfId=378629">
</A>
</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnLeft">
<A NAME="pgfId=378631">
</A>
</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqn">
<A NAME="pgfId=378633">
</A>
</P>
</TD>
</TR>
<TR>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnRight">
<A NAME="pgfId=378635">
</A>
</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnCenter">
<A NAME="pgfId=378637">
</A>
=</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnLeft">
<A NAME="pgfId=378639">
</A>
37,000 ms<SUP CLASS="Superscript">
–1</SUP>
</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnLeft">
<A NAME="pgfId=378641">
</A>
</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqn">
<A NAME="pgfId=378643">
</A>
</P>
</TD>
</TR>
</TABLE>
<P CLASS="BodyAfterHead">
<A NAME="pgfId=204372">
</A>
and <SPAN CLASS="EquationVariables">
t</SPAN>
<SUB CLASS="SubscriptVariable">
f</SUB>
<SPAN CLASS="Symbol">
ª</SPAN>
0.5 <SPAN CLASS="Symbol">
m</SPAN>
m/37,000 ms<SUP CLASS="Superscript">
–1</SUP>
<SPAN CLASS="Symbol">
ª</SPAN>
13 ps. </P>
<P CLASS="Body">
<A NAME="pgfId=206094">
</A>
The value for <SPAN CLASS="EquationNumber">
v</SPAN>
<SUB CLASS="Subscript">
max</SUB>
<SUB CLASS="SubscriptVariable">
n</SUB>
is lower than the 10<SUP CLASS="Superscript">
5</SUP>
ms<SUP CLASS="Superscript">
–1</SUP>
we expected because the carrier velocity is also lowered by <SPAN CLASS="Definition">
mobility degradation</SPAN>
due the vertical electric field—which we have ignored. This vertical field forces the carriers to keep “bumping” in to the interface between the silicon and the gate oxide, slowing them down.</P>
</DIV>
<DIV>
<H3 CLASS="Heading2">
<A NAME="pgfId=216082">
</A>
2.1.3 SPICE Models</H3>
<P CLASS="BodyAfterHead">
<A NAME="pgfId=216084">
</A>
The simulation program <SPAN CLASS="Definition">
SPICE</SPAN>
(which stands for <SPAN CLASS="Definition">
Simulation Program with Integrated Circuit Emphasis</SPAN>
) is often used to characterize logic cells. Table 2.1 shows a typical set of model parameters for our G5 process. The SPICE parameter <SPAN CLASS="BodyComputer">
KP</SPAN>
(given in <SPAN CLASS="Symbol">
m</SPAN>
AV<SUP CLASS="Superscript">
–2</SUP>
) corresponds to k<SUP CLASS="Superscript">
'</SUP>
<SUB CLASS="SubscriptVariable">
n</SUB>
(and k<SUP CLASS="Superscript">
'</SUP>
<SUB CLASS="SubscriptVariable">
p</SUB>
). SPICE parameters <SPAN CLASS="BodyComputer">
VT0</SPAN>
and <SPAN CLASS="BodyComputer">
TOX</SPAN>
correspond to <SPAN CLASS="EquationNumber">
V</SPAN>
<SUB CLASS="Subscript">
t</SUB>
<SUB CLASS="SubscriptVariable">
n</SUB>
(and <SPAN CLASS="EquationNumber">
V</SPAN>
<SUB CLASS="Subscript">
t</SUB>
<SUB CLASS="SubscriptVariable">
p</SUB>
), and <SPAN CLASS="EquationNumber">
T</SPAN>
<SUB CLASS="Subscript">
ox</SUB>
. SPICE parameter <SPAN CLASS="BodyComputer">
U0</SPAN>
(given in cm<SUP CLASS="Superscript">
2</SUP>
V<SUP CLASS="Superscript">
–1</SUP>
s<SUP CLASS="Superscript">
–1</SUP>
) corresponds to the ideal <SPAN CLASS="Definition">
bulk mobility</SPAN>
values, <SPAN CLASS="Symbol">
m</SPAN>
<SUB CLASS="SubscriptVariable">
n</SUB>
(and <SPAN CLASS="Symbol">
m</SPAN>
<SUB CLASS="SubscriptVariable">
p</SUB>
). Many of the other parameters model velocity saturation and mobility degradation (and thus the effective value of k<SUP CLASS="Superscript">
'</SUP>
<SUB CLASS="SubscriptVariable">
n</SUB>
and k<SUP CLASS="Superscript">
'</SUP>
<SUB CLASS="SubscriptVariable">
p</SUB>
).</P>
<TABLE>
<TR>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableTitle">
<A NAME="pgfId=216110">
</A>
TABLE 2.1 SPICE parameters for a generic 0.5 <SPAN CLASS="Symbol">
m</SPAN>
m process, G5 (0.6 <SPAN CLASS="Symbol">
m</SPAN>
m drawn gate length). The n-channel transistor characteristics are shown in Figure 2.4.</P>
</TD>
</TR>
<TR>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Computer">
<A NAME="pgfId=216116">
</A>
.MODEL CMOSN NMOS LEVEL=3 PHI=0.7 TOX=10E-09 XJ=0.2U TPG=1 VTO=0.65 DELTA=0.7<BR>
+ LD=5E-08 KP=2E-04 UO=550 THETA=0.27 RSH=2 GAMMA=0.6 NSUB=1.4E+17 NFS=6E+11<BR>
+ VMAX=2E+05 ETA=3.7E-02 KAPPA=2.9E-02 CGDO=3.0E-10 CGSO=3.0E-10 CGBO=4.0E-10<BR>
+ CJ=5.6E-04 MJ=0.56 CJSW=5E-11 MJSW=0.52 PB=1<BR>
.MODEL CMOSP PMOS LEVEL=3 PHI=0.7 TOX=10E-09 XJ=0.2U TPG=-1 VTO=-0.92 DELTA=0.29<BR>
+ LD=3.5E-08 KP=4.9E-05 UO=135 THETA=0.18 RSH=2 GAMMA=0.47 NSUB=8.5E+16 NFS=6.5E+11<BR>
+ VMAX=2.5E+05 ETA=2.45E-02 KAPPA=7.96 CGDO=2.4E-10 CGSO=2.4E-10 CGBO=3.8E-10<BR>
+ CJ=9.3E-04 MJ=0.47 CJSW=2.9E-10 MJSW=0.505 PB=1</P>
</TD>
</TR>
</TABLE>
</DIV>
<DIV>
<H3 CLASS="Heading2">
<A NAME="pgfId=85511">
</A>
2.1.4 Logic Levels</H3>
<P CLASS="BodyAfterHead">
<A NAME="pgfId=72954">
</A>
Figure 2.5 shows how to use transistors as logic switches. The bulk connection for the <SPAN CLASS="EmphasisPrefix">
n</SPAN>
-channel transistor in Figure 2.5(a–b) i⌨️ 快捷键说明
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