Klaus Oberhauser

Distance measurement sensor with PIN-photodiode and bridge circuit

The presented integrated optical distance measurement sensor works on the time-of-flight principle. The distance information is obtained from the correlation of received light and the transmitted signal. The PIN-bridge circuit concept ensures suppression of background light by equally charging and discharging the capacitor within one period, while integrating the wanted signal. The advantages of the included PIN-photodiode are high bandwidth f/sub 3 dB/>1.35 GHz together with high responsivity R=0.36 A/W at 660 nm. A single distance measurement is performed in 2 ms. With averaging, an accuracy of better than 1% is achieved for distances up to 3.7 m. Effective pixel size is 250/spl times/200 /spl mu/m/sup 2/ having a fill-factor of /spl sim/16%. The sensor was manufactured in a 0.6-/spl mu/m BiCMOS process.

Integrated BiCMOS p-i-n Photodetectors With High Bandwidth and High Responsivity

The integration of the fast and efficient silicon p-i-n photodetectors is presented. The suggested advanced p-i-n design speeds up the detectors, avoiding slow carrier diffusion: the p+ anode is arranged in a thick n

Distance Measurement Line Sensor with PIN Photodiodes

low-doped intrinsic region placed inside an n+ -doped region. Two p-i-n detector concepts are compared: a plain p-i-n photodiode and a structured p-i-n fingerdiode that is optimized for shorter wavelengths. Due to this setup and a thick intrinsic region, a responsivity of R=0.25 A/W (0.42 A/W) {0.27 A/W} at a wavelength of lambda=410 nm (660 nm) {850 nm} for the p-i-n fingerdiode, a bandwidth up to f3dB=3GHz and a dark current of Idark=0.36 pA at Vp-i-n=17 V for the p-i-n photodiode could be reached. As a system-on-chip (SOC), BiCMOS circuitry is combined with the integrated photodetector to an optoelectronic integrated circuit (OEIC) as shown on an exemplary application of a 6-Gb/s monolithic optical receiver. The chips are realized in a modified 0.5 mum BiCMOS process

Correlating PIN-photodetector with novel difference-integrator concept for range-finding applications

A 32 pixel line sensor is presented for range finding applications of non-cooperative targets based on the time-of-flight (TOF) principle of modulated light. The sensor is realized as an optoelectronic integrated circuit (OEIC) containing the PIN photodiode with a high bandwidth of >1 GHz together with a high responsivity of 0.45 A/W at 660 nm and a novel, quasi differential correlating active integrator circuit in each pixel. Distance information is gained in every pixel, integrating the weak received signal correlated with the transmitted modulation signal. The single pixel achieves a minimum standard deviation of 8.5 mm in a measurement range of 1.5 m - 3.2 m with an optical transmission power of 1.5 mW and a plain white paper target. Exemplarily a scanned 3D depth image of the university logo demonstrates the potential of the sensor. Single pixel size is 210 mum times 105 mum with an optical fill factor of 45%. The sensor chip was fabricated in a 0.6 mum BiCMOS process including PIN-technology.

Monolythically Integrated Optical Distance Measurement Sensor with Double-Cathode Photodetector

Exploiting the benefits of PIN photodiodes, a correlating detector and a novel difference integrator concept were realized in a single-chip range-finder solution. The PIN photodetector performing already internal modulation has a responsivity of R=0.30A/W at 660nm. A bandwidth of f/sub 3dB/=250MHz with correlation gates on thin oxide, respectively 500MHz on field oxide were achieved. Both challenges of the distance measurement - high sensitivity for signals in the order of nW and accuracies of 1.6% (1.7%) for 10m (15m) - could be reached. The measurement range goes from 20cm to 15m. The chip was realized in a modified 0.6nm BiCMOS process. Effective pixel size is /spl sim/250 /spl times/170/spl mu/m/sup 2/ including the photoreceiver of /spl sim/100 /spl times/ 100 /spl mu/m/sup 2/ resulting in a fill factor of /spl sim/24%.

Universal integrated PIN photodetector

The presented distance measurement sensor is implemented as an opto-electronic integrated circuit (OEIC) in a modified 0.6 mum BiCMOS technology. The measurement principle is based on the determination of the phase shift between a received optical signal and an electrical modulation signal. The newly developed double-cathode photodetector (DCP) performing the opto-electronic correlation and the all-passive read-out circuit are implemented on a single chip. By using the DCP the fill factor is greatly improved compared to K. Oberhauser et al (2006). For an optical active area of Apd = 115times120 mum2 a very high fill factor of etafill = 67 % is reached. The sensor is capable of measuring distances up to sd = 6.2 m with an optical transmitted power of Popt = 1.2 mW at a wavelength of lambda = 650 nm.

PIN-bridge distance measurement sensor

The universal PIN photodetector being realisable in CMOS and BiCMOS technology consists of a common cathode and finger anodes embedded in an intrinsic environment, for fast photogenerated-charge-carrier drift. This finger-anode structure, with rise times below 1 ns, and high responsivity in a wavelength range from 400 nm to 850 nm, permits applications: (i) as a two-anode correlation sensor for optical distance measurements and integrated 3D cameras; and (ii) as a photodiode for optical storage systems CD-ROMs as well as red and blue laser DVDs.

Time-of-flight based pixel architecture with integrated double-cathode photodetector

The presented integrated optical distance measurement sensor works on the time-of-flight principle. The distance information is obtained from the correlation of received light and the transmitted signal. The PIN-bridge circuit concept ensures suppression of background light by equally charging and discharging a capacitor within one period, while integrating the wanted signal. A single distance measurement is performed in 8 ms. With averaging, an accuracy of better than 1% is achieved for a distance of 3.7 m. Effective pixel size is 150/spl times/200 /spl mu/m/sup 2/ having a fill-factor of /spl sim/10%. The sensor was manufactured in a modified standard 0.6 /spl mu/m BiCMOS process.

Fast and efficient integrated silicon PIN-finger photodetector from ultraviolet up to near infrared

For various industrial applications contact-less optical 3D distance measurement systems with active illumination are suitable. A new approach for a pixel of such a 3D-camera chip for applications in displacement and 3D-shape measurement is presented here. The distance information is gained by measuring the Time-of-Flight (TOF) of photons transmitted by a modulated light source to a diffuse reflecting object and back to the receiver IC. The receiver is implemented as an opto-electronic integrated circuit (OEIC). It consists of a double-cathode photodetector performing an opto-electronic correlation, a decoupling network and an output low-pass filter on a single silicon chip. The correlation of the received optical signal and the electronic modulation signal enables the determination of the phase-shift between them. The phase-shift is directly proportional to the distance of the object. The measurement time for a single distance measurement is 20 ms for a range up to 6.2 m. The standard deviation up to 3.4 m is better than 1cm for a transmitted optical power of 1.2 mW at a wavelength of 650 nm. The OEIC was fabricated in a slightly modified 0.6 &mgr;m BiCMOS technology with a PIN-photodetector. The photosensitive area of the integrated PIN-photodetector is 120x115 &mgr;m2. A fill factor of ~67% is reached.

Correlating buried-finger photodetector for time-of-flight applications

Results of an integrated silicon PIN-photodetector with structured anode fingers are presented. As an improvement to homogenous photodiodes, a structured detector for the visible range with anode fingers is shown. A PIN-design was realized to speed up the detector, avoiding slow carrier diffusion: the p/sup +/ doped finger-anode is arranged in a thick n/sup +/ low doped intrinsic region placed inside an n/sup +/ doped region. Due to this setup and a thick intrinsic region, a responsivity of R = 0.25 A/W (0.43 A/W) at a wavelength of 410 nm (660 nm) could be reached. The achieved bandwidth of the detector in the visible range is up to 3 GHz. The photodiode was realized in a modified 0.5 /spl mu/m BiCMOS process.