Title :
Hydrogen-induced piezoelectric effects in InP HEMT´s
Author :
Blanchard, Roxann R. ; Del Alamo, Jesus A. ; Adams, Stephen B. ; Chao, P.C. ; Cornet, Albert
Author_Institution :
MIT, Cambridge, MA, USA
Abstract :
In this letter, we have investigated hydrogen degradation of InP HEMT´s with Ti/Pt/Au gates. We have found that V/sub T/ shifts negative after exposure to hydrogen, and exhibits an L/sub G/ and orientation dependence. We postulate that /spl Delta/V/sub T/ is at least in part due to the piezoelectric effect. Hydrogen exposure leads to the formation of TiH/sub x/, producing compressive stress in the gate. This stress induces a piezoelectric charge distribution in the semiconductor that shifts the threshold voltage. We have independently confirmed TiH/sub x/ formation under our experimental conditions through Auger measurements. Separate radius-of-curvature measurements have also independently confirmed that Ti/Pt films become compressively stressed relative to their initial state after H/sub 2/ exposure.
Keywords :
Auger electron spectra; III-V semiconductors; high electron mobility transistors; hydrogenation; indium compounds; internal stresses; piezoelectricity; semiconductor device measurement; semiconductor device metallisation; semiconductor device reliability; Auger measurements; H/sub 2/; H/sub 2/ exposure; H/sub 2/-induced piezoelectric effects; InP; InP HEMT; Ti-Pt-Au; Ti/Pt/Au gates; TiH; TiH/sub x/; compressive stress; hydrogen degradation; orientation dependence; piezoelectric charge distribution; radius-of-curvature measurements; threshold voltage shift; Compressive stress; Degradation; Gold; HEMTs; Hydrogen; Indium phosphide; Lead; Piezoelectric effect; Stress measurement; Threshold voltage;
Journal_Title :
Electron Device Letters, IEEE
