DC Field Distribution in a '""Swept Intrinsic" 

 Semiconductor Configuration 



By R. C. PRIM 



(Manuscript received January 15, 1953) 



This paper contains an analysis of the dc field intensity distribution in 

 an idealized one-dimensional n-intrinsic-p semi-conductor configuration 

 biased in reverse. It gives some quantitative insight into the progressive 

 penetration of the field into the intrinsic region as the magnitude of the 

 bias voltage is increased. 



INTRODUCTION 



Possible applications have been suggested for semi-conductor con- 

 figurations involving intrinsic regions adjacent simultaneously to n- 

 and p-type extrinsic regions. The basic idea behind some of these pro- 

 posals is that a suitably large reverse bias voltage (n-regions positive 

 with respect to p- regions) will set up a substantial electric field in the 

 interior of the intrinsic region. This field would sweep most of the mobile 

 carriers out of the intrinsic material, producing a region of material 

 ("swept intrinsic") supporting a large field and having a high resistivity. 



This paper contains a dc analysis of an idealized one-dimensional 

 swept intrinsic structure with abrupt transitions from strongly n-type 

 to highly intrinsic to strongly p-type material. It gives some quantita- 

 tive insight into the penetration of the electric field into the intrinsic 

 region as the bias voltage is progressively increased. 



FORMULATION OF PROBLEM 



A one-dimensional structure will be considered having the distri- 

 bution of excess of donor conceptration over acceptor concentration 

 (Nd-Na) shown in Fig. 1. It will be supposed that N/ni and P/ui are ^ 

 1 and that a reverse bias voltage (Fig. 2) is applied between the bodies 

 of the n- and p-type regions, (n^ denotes the thermal equilibrium con- 



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