Electrical Study of Self-Assembled Ge Quantum Dots Embedded in P-Type Silicon. Temperature Dependent Capacitance Voltage and DLTS Study
| Periodical | Solid State Phenomena (Volumes 178 - 179) |
|---|---|
| Main Theme | Gettering and Defect Engineering in Semiconductor Technology XIV |
| Edited by | W. Jantsch and F. Schäffler |
| Pages | 67-71 |
| DOI | 10.4028/www.scientific.net/SSP.178-179.67 |
| Citation | Victor Tapio Rangel-Kuoppa et al., 2011, Solid State Phenomena, 178-179, 67 |
| Online since | August, 2011 |
| Authors | Victor Tapio Rangel-Kuoppa, Gang Chen, Wolfgang Jantsch |
| Keywords | Activation Energy, Deep Level, DLTS, Ge QDs, Ge Quantum Dots, TCV |
| Price | US$ 28,- |
The electrical properties of dome-shaped and pyramid-shaped Ge Quantum Dots (QDs) embedded in p-type Silicon are reported. Capacitance-Voltage (T-CV) characteristics are reported for the temperature range of 35 K to 296 K. The T-CV results showed the desired charge carrier density of the Silicon, on the order of 1016 cm-3, at room temperature. Two shoulders are observed in the CV curves between 270 K and 175 K. They are explained as charge stored in the dome- and pyramid-shaped QDs. Below 175 K, only one shoulder is observed in the CV measurements, attributed to charge trapped in dome-shaped QDs. The DLTS study confirms these results. Using a reverse bias between -0.1 V and -1 V two peaks are seen at 50 and 70 K. They are explained in terms of the boron state (the one at 50 K) and charged stored on pyramid-shaped Ge QDs (the one at 70 K). Increasing the reverse bias from -1 V to -1.4 V shows the appearance of a peak around 60 K, attributed to dome-shaped Ge QDs. At the same time, a shoulder appears around 100 K for -1 V, which extends to larger temperatures as the reverse bias magnitude is increased. The activation energies found are around 50 meV (due to Boron), 150 to 250 meV (due to pyramid-shaped Ge QDs), 300 to 350 meV (due to dome-shaped Ge QDs) and 425 meV (due to both dome- and pyramid-shaped Ge QDs).
