Question

Parameters for Silicon at room temperature (T=300K) u = 1,350 cm'/volt-sec u = 850 cm/volt-sec n = 1 x 10" /cm A block of intrinsic silicon with length=5 cm, width=1 mm, and height = 0.5 mm is used as a thermistor. A constant voltage of 2V is applied across the length of the thermistor (a) Calculate the current at room temperature The thermistor is next dipped in boiling water (100 degrees Celsius). (b) Calculate the n at the elevated temperature (c) Estimate u, and , at the elevated temperature. u can be approximated from the lowest doping profile of the date provided in Lecture Notes - Intro to Semiconductors. Assume that , changes by the same percentage as u.. (d) Calculate the current at the elevated temperature (e) What is the percentage change in current from that at room temperature?

Answer 1

Qu Coln Griven dala Paramitar for silicon at room Tempo in /valt see un = 1350 cm up = 95o an/ Valt-see A= 1x 10 x 5x10 2003 А 5x107m² واهمو 7 5cm 2 -3 SX10 cm lo nia 1x10 100/m² a Current at room Temir I= neue it's has both type of conduction particle election and poston Т. ред. + 1. eAn E et [p up a new banani Ja étni [eythin] E = 2 1.6x15 19x.x100 [13soraso] 4v/cm 5 44.8 1408X10 A/m² -9 I= TA I= 5x108 1408x109 Alam? I = 7040x10 1. оч лА 12.

ni at 100°c Tempo Agê -Eg/2kT - 3/2 how this formula Comes. energy banda familial in instinsic Semiconductor lies mid of - [Ec-EF]/KT np = niz Nc na - [Ep-Ev] /kr nils mb bz 3/2 No= h² put the value and get; 2 [2 amat KT [2A mi ki] 3/2 2 — Ер 14кт ni= Ave he T/ 100 + 273 2 373 3/2 ni at 300k is Güven. - Eg /2k(373) ni;= Ао е 3 (373) -Eg/260300 (300) niza to x + Eg/2k300 Eg/2k (313) nii 1373 3/2 e This term gives the low changes. nie 22 3/2 Miza 100%m 300 3/ 3/2 10 To nie= nii 373 300 373 300 niz miz 1.38x10'

d Current at elevated Temp. I- ACE (p lept nln b=n=nie -3 Is 5x10 X 1.6x15 9 TO x.4 1030 X10 [eptlen elp, and lep is not given this at this temp. qraph of nobility and tempo temp. assuming the same value I2= 1.38 x before value qollna toou na oll Percentage change, 264 xinh 2067 x 10 xloo 34.927. Iz - II Xloo I 4. ou xish This result based only the len and lep value at assumption because the looc you are not provided