Experimental verification of temperature coefficients of resistance for uniformly doped P-type resistors in SOI

Abstract

Many today's microsystems like strain-gauge-based piezoresistive pressure sensors contain doped resistors. If one wants to predict correctly the temperature impact on the performance of such devices, the accurate data about the temperature coefficients of resistance (TCR) are essential. Although such data may be calculated using one of the existing mobility models, our experiments showed that we can observe the huge mismatch between the calculated and measured values. Thus, in order to investigate the TCR values, a set of the test structures that contained doped P-type resistors was fabricated. As the TCR value also depends on the doping profile shape, we decided to use the very thin, 340 nm thick SOI wafers in order to fabricate the quasi-uniformly doped silicon layers ranging from 2 × 10 17 at cm −3 to 1.6 × 10 19 at cm −3 . The results showed that the experimental data for the first-order TCR are quite far from the calculated ones especially over the doping range of 10 18 -10 19 at cm −3 and quite close to the experimental ones obtained by Bullis about 50 years ago for bulk silicon. Moreover, for the first time, second-order coefficients that were not very consistent with the calculations were obtained.

Design and fabrication of piezoresistive p-SOI Wheatstone bridges for high-temperature applications

“…9 (a). In doing so, α was 249 ± 16 ppm/K and β was 3.6 ± 0.1 ppm/K 2 (N = 4), which is in very good agreement with [5] (α between 200 and 400 ppm/K/β between 5 and 11 ppm/K 2 ). The temperature drift of the p-SOI Wheatstone bridge is shown in fig.…”

“…resistors) was (0.0153 ± 12.3 ×10 -6 ) Ωcm (5×10 18 cm 3 ) and for the p ++ -silicon (0.0044 ± 24,5×10 -6 ) Ωcm (2.5×10 19 cm 3 ), respectively. The specific doping concentration for the resistors was chosen for achieving the lowest temperature coefficient for uniformly doped p-type resistors in SOI [5]. After the doping process, contact pads were coated with a high-temperature stable metallization system (Ti/Pd/Au or Ti/TiN/Au).…”

On the Feasibility of a New Approach for Developing a Piezoresistive 3D Stress Sensing Rosette

“…Cho et al studied the effect of temperature on the TCR value on heavily doped n-type resistors from C to 130 C. They concluded that a first-order TCR is adequate to model the function at high doping concentrations [35]. A similar conclusion is reached by Olszacki et al for p-type silicon, where the quadratic terms in were found to approach zero at high doping levels [36].…”

High-Performance Piezoresistive MEMS Strain Sensor with Low Thermal Sensitivity

“…The presented TCRs in Figure 18 are the combined effects of all orders TCRs in addition to the local effect of the geometric features. Values of TCRs were collected from literature [ 20 , 22 , 30 , 37 , 40 , 42 ] to perform further comparison. A similar procedure was used to calculate the TCRs from the published literature using the appropriate figures.…”