Gainassb Infrared Detector Devices And Physics

The band gap energy of compound semicon ductor GaInAsSb alloy rangs from 0.1 eV to 1.42eV, which covers three important infrared wavebands of l~3m 3~5m 8~12m. GalnAsSb alloy, whose lattice is matched to GaSb substrate with wavelength in the range of 1.7-4.3m, are of great interests for use as mid-infrared photodetectors operating at room temperature. The materil is important in infrared imaging, pollution monitoring, industrial process control and future fibre communication. GalnAsSb infrared detectors are novel compound detectors with advantages of fast response, high sensitivity, high stability, low price, especially its character to work at room temperature.The device technology is studied and the device performance is improved in this dissertation. Major contents and results of the study are abstracted as following:1. The dark current of PIN GalnAsSb infrared decectors is simulated. The PSPICE model of detector is set up. Simulated results coincided with tested results, trap assisted tunneling current dominated dark current of the devices when the reverse voltage was larger than 0.35V. Calculation show that the defects in the surface of device have great effect on the reverse characteristics of GalnAsSb infrared detectors.2. The omhnic contact and the annealing conditicn of p-type GalnAsSb and n-typeGaSb compound semiconductors are studied and the samples are analysed with SEM and XRD. Test results show that TiPtAU and AuZn on GalnAsSb have become omhnic contact. Omhnic contact of TiPtAu is smaller and stabler than that of AuZn. AuGeNi on N-type GaSb cann't become omhnic contact at room temperature. Annealing study shows that AtGeNi on N-type become omhnic contact above 295. There is no data at 305 and Concentration of pits is abserved. It is proved that the annealing temperature of AuGeNi on N-type GaSbis about 300?C. The contact restivity reaches to 10cm .3. The I-V character and detectivity are both improved after (NH4)2S passivation.The black body detectivity D was improve from 6.9 108 cm Hz1/2 W to 2.064 109 cm Hz1/2W after passivation at the testing condition of black body of 1000 K, central frequency of 1000 Hz, band with of 100 Hz. Reverse dark current of photodetectors was reduced and the peak detectivity reached 4.83 1010 cmHzW after passivation.Sulfur passivation. GalnAsSb was studied in terms of Auger Electron Spectrascopy(AES) and X-ray photoelectron spectroscopy(XPS). The experimental results showed that Sb-S bonds, In-S bonds exist on the sulphur passivated GalnAsSb surfaces. I-V characteristics of the passivated photodectors keeps almost unchangeable after more than 90 days in our experiment.4. The antireflective film is studied. Test results show that detectivity is improved 20%-40% after growing antireflective film on detectors. I-V character keeps almost unchanged. SiO is better antireflective film comparing with SiO2 A12O3 for GalnAsSb infrared detectors.5. The theory of low noise preamplifer of GalnAsSb infrared detectors is studied. Two preamplifers are made.