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1、Chapter 4 Semiconductor devices,4.1 Ideal pn junction4.2 pn Junction Band Diagram4.3 Bipolar Transistor4.4 Junction Field Effect Transistor4.5 Metal Oxide Semiconductor Field Effect Transistor4.6 Light Emitting Diodes4.7 Solar Cells,From Principles of electronic Materials Devices,SO Kasap(McGraw-Hil
2、l,2005),4.1 Ideal pn junction,4.1 Ideal pn junction,4.1 Ideal pn junction,4.1 Ideal pn junction,4.1 Ideal pn junction,4.1 Ideal pn junction,Considering an abrupt pn junction:net(x)can simply be described by step functions shown in Fig.(d).Using the step form of net(x)in Fig.(d)in the integration ofg
3、ives the electric field at M.,Integrate the expression for E(x)in Fig.(e)to evaluate the potential V(x)and thus find V0 by putting in x=Wn.,W0=Wn+Wp,is the total width of the depletion region under a zero applied voltage.,The simplest way to relate V0 to the doping parameters is to make use of the f
4、act that in the system consisting of p-and n-type semiconductors joined together,in equilibrium,Blotzmann statistics demands that the concentrations n1 and n2 of carriers at potential energies E1 and E2 are related by,Considering electrons(q=-e),we see from Fig.(g)that E=0 on the p side far away fro
5、m M where n=npo,and E=-eVo on the n-side away from M where n=nno.Thus,Which mean that Vo depends on nno and npo and hence on Nd and Na.The corresponding equation for hole concentrations is clearly,RearrangingAndWe obtainWe can now write ppo and pno in terms of the dopant concentrations inasmuch as p
6、po=Na and,Forward bias:diffusion current,Forward bias:diffusion current,Forward bias:diffusion current,(b),Forward bias:diffusion current,(b),Forward bias:diffusion current,Law of the junction is an important equation that we,(b),Forward bias:diffusion current,(b),Forward bias:diffusion current,(b),
7、Forward bias:diffusion current,(b),Forward bias:diffusion current,(b),Forward bias:diffusion current,Reverse biased pn junction.(a)Minority carrier profiles and the origin of the reverse current.,Reverse bias,Reverse biased pn junction.(a)Minority carrier profiles and the origin of the reverse curre
8、nt.,Reverse bias,Reverse biased pn junction.(b)Hole PE across the junction under reverse bias,Reverse biased pn junction.(a)Minority carrier profiles and the origin of the reverse current.,Reverse bias,positive,Reverse biased pn junction.(a)Minority carrier profiles and the origin of the reverse cur
9、rent.,Reverse biased pn junction.(a)Minority carrier profiles and the origin of the reverse current.,Reverse biased pn junction.(a)Minority carrier profiles and the origin of the reverse current.,Reverse biased pn junction.(a)Minority carrier profiles and the origin of the reverse current.,(a)Revers
10、e I-V characteristics of a pn junction(the positive and negative current axes have different scales).,(a)Reverse I-V characteristics of a pn junction(the positive and negative current axes have different scales).,4.2 pn Junction Band Diagram,4.2 pn Junction Band Diagram,4.2 pn Junction Band Diagram,
11、4.2 pn Junction Band Diagram,4.2 pn Junction Band Diagram,4.2 pn Junction Band Diagram,Forwardbias,Forwardbias,Forwardbias,Forwardbias,Forwardbias,Forwardbias,Energy band diagrams for a pn junction under(c)reverse bias conditions.,Reverse bias,Energy band diagrams for a pn junction under(c)reverse b
12、ias conditions.,Reverse bias,Reverse bias,Energy band diagrams for a pn junction under(d)Thermal generation of electron hole pairs in the depletion region results in a small reverse current.,Reverse bias,Energy band diagrams for a pn junction under(d)Thermal generation of electron hole pairs in the
13、depletion region results in a small reverse current.,4.3 Bipolar Transistor,(a)A schematic illustration of the pnp bipolar transistor with three differently doped regions.(b)The pnp bipolar operated under normal and active conditions.,4.3 Bipolar Transistor,4.3 Bipolar Transistor,4.3 Bipolar Transis
14、tor,(c)The CB configuration with input and output circuits identified,(b)The pnp bipolar operated under normal and active conditions.,Fig.(c)shows the CB transistor circuit with the BJT represented by its circuit symbol.The arrow identified the emitter junction and points in the direction of current
15、 flow when the EB junction is forward biased.Fig.(c)also identifies the emitter circuit,where VEB is connected,as the input circuit.The collector circuit,where VCB is connected,is the output circuit.,(c)The CB configuration with input and output circuits identified,(b)The pnp bipolar operated under
16、normal and active conditions.,(c)The CB configuration with input and output circuits identified,(b)The pnp bipolar operated under normal and active conditions.,(c)The CB configuration with input and output circuits identified,(b)The pnp bipolar operated under normal and active conditions.,(c)The CB
17、configuration with input and output circuits identified,(b)The pnp bipolar operated under normal and active conditions.,(c)The CB configuration with input and output circuits identified,(b)The pnp bipolar operated under normal and active conditions.,(c)The CB configuration with input and output circ
18、uits identified,(b)The pnp bipolar operated under normal and active conditions.,(c)The CB configuration with input and output circuits identified,(b)The pnp bipolar operated under normal and active conditions.,(c)The CB configuration with input and output circuits identified,(b)The pnp bipolar opera
19、ted under normal and active conditions.,(c)The CB configuration with input and output circuits identified,(b)The pnp bipolar operated under normal and active conditions.,(c)The CB configuration with input and output circuits identified,(b)The pnp bipolar operated under normal and active conditions.,
20、(c)The CB configuration with input and output circuits identified,(b)The pnp bipolar operated under normal and active conditions.,(c)The CB configuration with input and output circuits identified,(b)The pnp bipolar operated under normal and active conditions.,(b)The pnp bipolar operated under normal
21、 and active conditions.,(d)The illustration of various current components under normal and active conditions.,(b)The pnp bipolar operated under normal and active conditions.,(d)The illustration of various current components under normal and active conditions.,(b)The pnp bipolar operated under normal
22、 and active conditions.,(d)The illustration of various current components under normal and active conditions.,In t,a,(b)The pnp bipolar operated under normal and active conditions.,(d)The illustration of various current components under normal and active conditions.,(b)The pnp bipolar operated under
23、 normal and active conditions.,(d)The illustration of various current components under normal and active conditions.,(b)The pnp bipolar operated under normal and active conditions.,(d)The illustration of various current components under normal and active conditions.,(b)The pnp bipolar operated under
24、 normal and active conditions.,(d)The illustration of various current components under normal and active conditions.,(b)The pnp bipolar operated under normal and active conditions.,(d)The illustration of various current components under normal and active conditions.,(b)The pnp bipolar operated under normal and active conditions.,(d)The illustration of various current components under normal and active conditions.,(b)The pnp bipolar operated under normal and active conditions.,(d)The illustration of various current components under normal and active conditions.,
