Ultra-Fast Image Sensor Using Ge on Insulator MIS/Schottky Detectors
Abstract
The Ge-on-insulator has been fabricated by wafer bonding and smart-cut. The MIS structure leads to simple fabrication process as compared to the conventional PIN structure. Due to the small band gap of Ge, 1.3 microns and 1.55 microns infrared beside 850 nm can be detected. The low parasitics of GOI structure also increase the detection speed. The large work function metal (Pt) is used for the gate electrode to reduce the dark current of the MIS tunneling diode. Chemical etching is an effective method to remove the implantation damage in order to reduce the dark current and increase the responsivities of visible light. The major achievements are: 1. Thin film Ge on oxide on Si has been demonstrated with smart-cut and wafer bonding at low temperature as low as 150 deg. C, and the detector has been fabricated using simple MIS structure. 2. Responsivity up to 0.2 A/W can be obtained for 850 nm and 1.3 microns infrared. 3. The dark current of the GOI MIS detector at -2 V can be decreased by a factor of 18 as compared to the GOI SB detector. 4. External mechanical strain can further enhance the photo current, while the dark current variation is smaller than 2 %. 5. Higher operational speed can be achieved with a Ge-on-insulator detector as compared to the bulk Ge detector. 6. Thin film Ge can be used for visible light detection. The red- and green- responses have been measured.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 28, 2008
- Accession Number
- ADA481999
Entities
People
- Chee-wee Liu
Organizations
- National Taiwan University