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One dimensional process and device simulation using spreadsheets 
 


Authors 
 Krupkina T.Yu. 
 Krasukov A.Yu. 
 Artamonova Ye.A. 
Date of publication 
 2016 

Abstract 
 Device simulation programs for onedimensional modeling of MISstructures and pnjunctions, and silicon process simulation tools were created using spreadsheets.
Development of new semiconductor devices and process flows is almost impossible without process and device simulation. Usually it is necessary to estimate dependencies of the device parameters (such as threshold voltage, gate capacitance, breakdown voltage) versus the process modes (such as ion implantation dose and energy, oxidation and doping diffusion time and temperature).
Existing commercial simulation tools – TCAD form Synopsys [1] or Silvaco [2] are widely used for multidimensional modelling of different semiconductor devices and processes.
However such tools are very complex for studying (manuals for Sentaurus Device from Synopsys TCAD F2011.09 have 1334 pages), occupy a lot of HDD memory and usually operates under OS Linux.
For initial estimation of silicon device parameters and technological process modes it will be useful to have small, simple, fast and user friendly programs such as very popular Process Wizard (Prowize or FAKT) the one dimensional process simulator developed still under MSDOS.
It will be useful to utilize the Microsoft Excel spreadsheets as the basis for 1Dsimlutors. Spreadsheet has simple and comfortable tools for 1Ddata storing and visualization. For example in [3] were developed twodimensional program PC2D for solar cells device simulation, completely based on Excel spreadsheets.
In this article we develop several programs for one dimensional silicon process and devices simulation, based on Microsoft Excel spreadsheets. In our programs the main computation core is realized in Visual Basic, embedded in Excel [4]. There are three main programs:
 device simulation of metalinsulatorsemiconductor (MIS)structures and transistors MIS1D;
 device simulation of pnjunctions PN1D;
 silicon technology process simulation Process1D.
MIS1D program can build onedimensional MIS
structure model with five different materials such as
Si, SiO2, Si3N4 and three other insulators with user defined parameters. Donor and acceptor concentrations can be defined as constant and Gaussian profiles. MIS model is covered by nonuniform finitedifference grid. The grid is automatically refined at region interfaces according to userdefined minimum and maximum step. MIS1D solves numerically the Poisson equation with several models and material parameters (permeability, electron affinity, band gap, intrinsic density). MIS1D is a single Excel file with two spreadsheets – the first for simulation results, and the second – for model parameters. As a result MIS1D computes and visualizes spatial distributions of potential, electric field, carrier concentrations and band diagrams. Also MIS1D computes the inversion charge–voltage and CV characteristics at different gatesubstrate voltages.
PN1D program can build onedimensional silicon pnmodels (p+n, n+p, p+pn, n+np, n+pp+, p+nn+). with nonuniform doping distribution. The finitedifference grid is refined at pnjunction depth (Xj) according to userdefined minimum and maximum step. PN1D can compute the surface resistance (ρs) of doping region, what allows restoring the unknown profile by given ρs and Xj. PN1D can solve the single Poisson equation for reversebiased pnjunction (with constant quasiFermi levels) at linear (1D), cylindrical (2D) and spherical (3D) coordinates and compute the avalanche breakdown voltage and pnjunction CVcharacteristics at different voltages. Also PN1D can solve the driftdiffusion system (Poisson and two carrier continuity questions) in linear coordinates and compute IVcharacteristics for the forward and reverse biased pnjunction).
Process1D can model silicon process operations such as ion implantation, oxidation and diffusion for B, P,As impurities and N2,O2,H2O ambients. Ion implantation simulated using Gaussian distributions. Oxidation and diffusion simulated by solving numerically the second Fick law equation for impurities and oxidants. 
Keywords 
 process and device simulation, TCAD, one dimensional approach, spreadsheets. 
Library reference 
 Krupkina T.Yu., Krasukov A.Yu., Artamonova Ye.A. One dimensional process and device simulation using spreadsheets // Problems of Perspective Micro and Nanoelectronic Systems Development  2016. Proceedings / edited by A. Stempkovsky, Moscow, IPPM RAS, 2016. Part4. P. 2431. 
URL of paper 
 http://www.mesconference.ru/data/year2016/pdf/D083.pdf 

