Visible-Blind UV/IR Photodetectors Integrated on Si Substrates
- PDF / 149,691 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 21 Downloads / 161 Views
0934-I09-04
Visible-Blind UV/IR Photodetectors Integrated on Si Substrates David Starikov1,2, John Chris Boney1,2, Rajeev Pillai2, and Abdelhak Bensaoula2 1 Integrated Micro Sensors Inc., 10814 Atwell Dr., Houston, 77096 2 CAM, University of Houston, 724 Science & Research Bldg. 1, Houston, 77004 ABSTRACT A concept based on structures fabricated using stacked semiconducting layers to obtain a multi spectral photoresponse is investigated. Issues related to III nitride layer growth on thin Si wafers, such as substrate temperature recalibration and mechanical stress due to the lattice mismatch, have been studied. The grown on Si substrate III nitride layers were characterized by using spectroscopic ellipsometry and capacitance measurements. Fabrication of a dual-band UV/IR photodetector with a reasonable responsivity at room temperature has been demonstrated. The integrated device is capable of detecting optical emissions separately in the UV and IR parts of the spectrum. The responsivities of this device are ~0.01 A/W, at a peak wavelength of 300 nm and ~0.08 A/W, at a peak wavelength of 1000 nm, respectively. The described dual-band photodetectors can be employed for false alarm-free fire/flame detection and advanced hazardous object or target detection and recognition in several industrial, military, and space applications. INTRODUCTION Si and some III-V compounds are perfect for detection in the visible (VIS) and near infrared (IR) range, and wide bandgap semiconductor materials, such as diamond, SiC, and III nitrides, are superior for applications in the ultraviolet (UV) range. Several military and industrial applications require simultaneous (or at least spatially registered/synchronized) detection of optical emissions in different spectral regions. Significant progress has been made lately in the development of UV detectors based on wide band gap materials [1]. Group III nitride materials are superior for advanced UV detector fabrication due to their wide direct band gap and high thermal, chemical, mechanical, and radiation tolerance. A large amount of research has been dedicated lately to the development of UV detectors based on GaN [2], GaN/AlGaN [3], and AlGaN [4]. In the area of IR detection, HgCdTe- and InSb-based detectors [1] and detectors based on heterointernal photoemission (HIP) in GexSi1-x/Si heterojunctions [5] are still leading the market. However, such devices are limited to operation under cooled conditions, such as cryogenic temperatures or even lower. The opportunity to grow III nitrides on Si wafers can be considered as the main key to the development of integrated multi-color detectors ranging from the UV to IR. Device-quality GaN layers have been demonstrated lately [6]. In this work, we demonstrated fabrication and characterization of a UV/IR visible-blind photodetector based on stacked semiconducting layers with desired properties, integrated on a single chip. The fabrication of the device is based on the growth of III nitride compounds on commercial Si wafers by Radio-Frequency Molecular
Data Loading...
