Processing and characterization of epitaxial GaAs radiation detectors

作者：Wu X^*; Peltola T; Arsenovich T; Gadda A; Harkonen J; Junkes A; Karadzhinova A; Kostamo P; Lipsanen H; Luukka P; Mattila M; Nenonen S; Riekkinen T; Tuominen E; Winkler A

来源：Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment , 2015, 796: 51-55.

DOI：10.1016/j.nima.2015.03.028

• GaAs
• Solid state radiation detectors
• Wafer processing
• Defect characterization
• TCAD simulations

GaAs devices have relatively high atomic numbers (Z=31, 33) and thus extend the X-ray absorption edge beyond that of Si (Z=14) devices. In this study, radiation detectors were processed on GaAs substrates with 110-130 mu m thick epitaxial absorption volume. Thick undoped and heavily doped p(+) epitaxial layers were grown using a custom-made horizontal Chloride Vapor Phase Epitaxy (CVPE) reactor, the growth rate of which was about 10 mu m/h. The GaAs p(+)/i/n(+) detectors were characterized by Capacitance Voltage (CV), Current Voltage (IV), Transient Current Technique (TCT) and Deep Level Transient Spectroscopy (DLTS) measurements. The full depletion voltage (V-fd) of the detectors with 110 mu m epi-layer thickness is in the range of 8-15 V and the leakage current density is about 10 nA/cm(2). The signal transit time determined by TCT is about 5 ns when the bias voltage is well above the value that produces the peak saturation drift velocity of electrons in GaAs at a given thickness. Numerical simulations with an appropriate defect model agree with the experimental results.

• 出版日期2015-10-1