Browse Prior Art Database

Contact of Silicide on p-Type Si

IP.com Disclosure Number: IPCOM000086565D
Original Publication Date: 1976-Sep-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Tu, KN: AUTHOR

Abstract

Contact on Si that offers a high Schottky barrier is important for rectifying purpose in high performance device. The common one is PtSi on n-type Si which gives a Schottky barrier Phi(B) = 0.87 eV. Recently, an empirical was provided [1] that relates Phi(B) and Delta H for silicides on Si: Phi/n-Si/(B) = 0.81 + 0.17 Delta H where Phi(B) is Schottky barrier height and Delta H is heat of formation of silicide in eV unit normalized per metallic atoms. The formula indicates that Phi(B) will be small on n-type Si for large Delta H. Collected information Delta H is shown in Table I. It is noted that the Delta H of VSi(2) is extremely high, about 73 Kcal/mole or 3.2 eV per V atom. It can be shown that: Phi(B)/VSi2/nSi/ = 0.81 - 0.17 x 3.2 = 0.25 eV Since Phi(B)/n-Si/ + Phi(B)/p-Si/ = 1.1 eV we obtain Phi(B)/VSi 2 /p-Si/ = 1.

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Contact of Silicide on p-Type Si

Contact on Si that offers a high Schottky barrier is important for rectifying purpose in high performance device. The common one is PtSi on n-type Si which gives a Schottky barrier Phi(B) = 0.87 eV. Recently, an empirical was provided [1] that relates Phi(B) and Delta H for silicides on Si: Phi/n-Si/(B) = 0.81 + 0.17 Delta H where Phi(B) is Schottky barrier height and Delta H is heat of formation of silicide in eV unit normalized per metallic atoms. The formula indicates that Phi(B) will be small on n-type Si for large Delta H. Collected information Delta H is shown in Table I. It is noted that the Delta H of VSi(2) is extremely high, about 73 Kcal/mole or 3.2 eV per V atom. It can be shown that: Phi(B)/VSi2/nSi/ = 0.81 - 0.17 x 3.2 = 0.25 eV Since Phi(B)/n-Si/ + Phi(B)/p-Si/ =
1.1 eV we obtain Phi(B)/VSi 2 /p-Si/ = 1.1 - 0.25 = 0.85 eV

The values show that VSi(2) can be used as a good rectifying contact on p- type Si and a good ohmic contact on n-type Si. The high Delta H of VSi(2) offers another advantage in that it is more stable than other silicides with respect to the reaction with aluminum. It is known that VSi(2) can form around 550 degrees C by reacting vanadium thin film and Si wafers [2]. [1] J. M. Andrews and J. C. Phillips, Phys. Rev. Letters, 35, 56 (1975). [2] K. N. Tu, J. F. Ziegler and C. J. Kircher, Appl. Phys. Letters, 23, 493 (1973).

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