Specific contact resistance of metal-semiconductor barriers

doi:10.1016/0038-1101(71)90129-8

Solid-State Electronics

Volume 14, Issue 7, July 1971, Pages 541-550

https://doi.org/10.1016/0038-1101(71)90129-8 Get rights and content

Abstract

The specific contact resistance at zero bias, R_c, serves as a measure of the ohmic or rectifying behavior of a metal-semiconductor barrier under operating conditions. It is thus an important design parameter for semiconductor devices. The values of R_c have been calculated for Metal-Si and metal-GaAs barriers on p-type and n-type samples. The theoretical calculation is based on the generalized transport study of metal-semiconductor systems.

The results, which are presented graphically, show the dependence of R_c on temperature over the range 50°K–500°K, the barrier height from 0.2 to 1.0 eV, and the ionized impurity concentration from 10¹⁴ to 10²¹ cm⁻³. Generally R_c decreases exponentially with increasing temperature and with decreasing barrier height. For samples with lower dopings where the thermionic emission dominates, R_c is essentially independent of doping; for higher dopings where the tunneling dominates, R_c decreases rapidly with increasing doping. The experimental results of R_c for various metals on silicon samples are in good agreement with the predictions.

Résumé

La résistance de contact spécifique à polarisation nulle, R_c, sert de mesure du comportement ohmique ou de redressement d'une barriere métal-semiconducteur dans des conditions de fonctionnement. Il est ainsi important en tant que paramètre de conception pour les dispositifs semi conducteurs. Les valeurs de R_c ont été calculées pour les barrières métal-Si et métal-GaAs sur des échantillons du type —p et du type —n. Le calcul théorique est fondé sur l'étude de transport généralisé de systèmes métal-semiconducteurs.

Les résultats, présentés graphiquement, montrent la dépendance de R_c sur la température dans la gamme de 50°K à 500°K, la hauteur de barrière entre 0,2 et 1,0 eV, et la concentration d'impureté ionisée entre 10¹⁴ et 10²¹ cm⁻³. Généralement R_c diminue exponentiellement avec l'accroissement de température et avec le décroissement de la hauteur de barrière. Pour les échantillons avec doping plus faible où l'émission thermoionique domine, R_c est essentiellement indépendant du doping; pour un doping plus élevé où le tunnellement domine, R_c décroit rapidement à mesure que le doping augmente. Les résultats expérimentaux de R_c pour divers échantillons de métal sur silicium sont en bon accord avec les prévisions.

Zusammenfassung

Bei einem Halbleiter-Metall-Kontakt unter Betriebsbedingungen dient der spezifische Kontaktwiderstand R_c ohne Vorspannung als Maß für ohmsches Verhalten oder Gleichrichterwirkung. Er ist daher eine wichtige Größe bei der Konstruktion von Halbleiterbauelementen. Die Werte für R_c wurden für Metall-Silizium- und Metall-Galliumarsenid-Barrieren mit p- oder n-Typ Kristallen berechnet. Die theoretische Rechnung beruht auf einer verallgemeinerten Studie der Transporteigenschaften eines Metall-Halbleiter-Systems.

Die graphisch wiedergegebenen Ergebnisse zeigen den Verlauf von R_c für einen Temperaturbereich von 50°K bis 500°K, Barrierenhöhen zwischen 0,2 und 1,0 eV und Konzentrationswerte der ionisierten Störstellen von 10¹⁴/cm³ bis 10²¹/cm⁻³. Ganz allgemein nimmt R_c mit der Temperatur ab und mit der Barrierenhöhe zu. Bei Proben mit niedrigerer Dotierung, wo die thermische Emission überwiegt, ist R_c im wesentlichen von der Konzentration unabhängig. Mit höherer Dotierung nimmt R_c rasch wegen des überwiegenden Tunnelstromes ab. Die experimentellen Ergebnisse für R_c mit verschiedenen Metallen auf Silizium sind in guter Übereinstimmung mit den vorhergesagten Werten.

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Specific contact resistance of metal-semiconductor barriers

Abstract

Résumé

Zusammenfassung

Solid-St. Electron.

Solid-St. Electron.

Solid-St. Electron.

Solid-St. Electron.

Solid-St. Electron.

J. appl. Phys.