A scientific parallel processor called the R256 has been developed. The R256 is composed of 16x16 processing elements, and has the outstanding features of a “distributed parallel network” as well as on IEEE 80-bit extended floating point computation ability. The computation accuracy, required by an exhaustive number of iterations in scientific computations, is resolved by the dedicated 80-bit VLSI processor, which was developed here for the R256. The innovative distributed parallel network was designed so as to effectively resolve heavy communication problems, which are found in applications based on the Monte Carlo simulation technique. The R256 network was very economical at a hardware cost of √N-folds (16 folds in this case) to that of an ideal full-crossbar switch, at the same time keeping the rates comparable to that of an ideal switch. The R256 demonstrates high performance of 2-GB/s data transfer rates and 500-MFLOPS computation rates on a semiconductor device simulation application.

An application of Monte Carlo particle and relaxation time approximation modeling to quarter-micron Si MOSFETs is presented. Through a comparison between these two nonstatic models and a conventional model, nonstationary carrier transport is shown to dominate in 0.4 mu m or less channel devices, with peak velocities exceeding 1.0*10/sup 7/ cm/s. It is shown that the relaxation time approximation model tends to overestimate nonstationary carrier dynamics, especially the energy distribution.>

The current status of semiconductor device simulation at NTT is described. Device simulators at NTT are classified into two categories. One is the conventional macroscopic approach and the other is microscopic particle analysis using a Monte Carlo method. In this paper, these simulators are introduced together with the more interesting results. Through these examples, it is demonstrated that the device simulation takes an important role for accurate modeling of semiconductor devices. This report also concludes that the choosing the best simulation program for a given problem is the key to obtain effectively an accurate solution.