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A simple DC method for measurement of the capture cross-sections at the Si/SiO2 interface is presented. The method combines the measurement of the interface recombination current under the gate of the MOS transistor with the measurement of the subthreshold slope. The results are in good agreement with previous results obtained by AC small-signal and transient methods.

A new experimental methodology for the analysis of Si/GexSi1–x/Si HBT yields quantitative values for the important transistor parameters, such as the energy gap reduction and the built-in electric field due to Ge, and the minority-carrier base diffusion length, lifetime and transit time. The method also enables a charge-control analysis of the base current to be made. A demonstration is presented for a GeSi heterojunction bipolar transistor with a linearly graded Ge profile in the base. The methodology can be extended for arbitrary material composition and doping profile in the base.

A new interface trap generation pathway is demonstrated in MOS transistors. The pathway is due to the electrical activation or dehydrogenation of the electronic traps at the SiO/sub 2/-Si interface via chemical reduction by atomic hydrogen released from the interconnect during high-current density low-voltage stress.

A channel hot carrier current and the failure rate of n- and p-channel MOS transistors are both increased by one to two orders of magnitude by forward biasing the substrate or source pin junction. Correlations with the hydrogen-bond-breaking theory give a threshold kinetic energy of 3.06/spl plusmn/0.05 eV for interface trap generation by hot carriers.

Performance improvements of Si/Ge/sub x/Si/sub 1-x//Si heterojunction bipolar transistors with linearly graded Ge profile in the epitaxial base layer are compared with Si transistors without Ge by using a combined DC and low-frequency (1 kHz) small-signal AC measurements. Quantitative analysis of the minority-carrier transport parameters in the GeSi base layer, and of the current gain and recombination current components, for both GeSi and Si transistors are reported for the first time. The two fold improvement of the base transit time in GeSi transistors is due to the built-in electric field from Ge grading, rather than to improved diffusivity.

An experimental method is presented for the direct measurement of the built-in electric field in Si/GexSi1–x/Si heterojunction bipolar transistors (HBT) with a linearly-graded Ge profile. The method is based on a comparison of the DC and AC characteristics of Si/GexSi1–x/Si HBTs and reference Si bipolar transistors with the same geometry and doping profiles. The built-in field is determined independently of the density of states, minority-carrier mobility, and heavy-doping effects.

The concept of using switched currents through a single p-n junction for a linear temperature measurement as proposed by Freire et al. (Apr. 1994) has been previously described by J. Williams (1991). Williams uses asynchronous set of switches (LTC 1043) to switch separate currents through a diode-connected transistor, and also to switch capacitors synchronously with the currents. This action creates an output that is proportional to the peak-to-peak voltage of the sensor. The circuit uses relatively few components. There are, however, some design errors in the the current generator that he uses. It was pointed out to Williams that trimming is necessary due to component tolerances, and a simpler and more accurate means of generating the two selected currents was proposed (May 1991). >

The commenter notes that by equating the real and imaginary parts of (3) to zero, the author of the above-titled paper (ibid., vol.39, p.795-7, Oct. 1990) obtains the frequency and condition of oscillation (4) and (5). He points out that as a result, (5) implies that g cannot be varied if G/sub 2/ is a fixed quantity, therefore negating (6)-(8). He proposes instead to find the roots of the characteristic equation to find the full conditions for oscillation and startup and shows how this is done. >